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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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Sony STR-DE635 recieiver won't power up
First off I'd like to say, "Hello." to the group. I hope I can gain
some knowledge from the group's collective input. I have a Sony STR-DE635 stereo receiver that will not turn on and I would like to investigate into maybe seeing if I can repair it. I found a set of schematics on this site which I believe will definitely help.(http://www.eserviceinfo.com/index.php?what=search2) I'm guessing but I think that the problem is related to the power supply? On p.13 of this .PDF manual it has an A/C and D/C schematic, this receiver has a seperate board for each. I probed the A/C board and found that it has voltage out to the "Digital" board of a little over 12 volts but when I try to test the pins on CNV902 I thought I should be getting appx. 110 A/C but only get appx. 2? CNV902 is a simple 2 wire connector leading directly to a transformer. My common sense is telling me that why would I need a transformaer the size of Kansas for only 2 volts A/C? So, I'm guessing this might have something to do with it? I could be in left field due to my lack of knowledge and inexperience, that's why I'm hoping you guy's/girl's can shed some light. Thanks for any suggestions or hints you can provide. |
#2
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These sets can be very difficult to reliably and safely troubleshoot and
service. The proper training, service experience, product training, and a solid background in electronics theory would be an asset to do service on these sets. In going by the way you are presenting your questions, I would suggest you give the unit out to an authorized service centre to have an estimate done for you. When servicing these sets, the main procedure is to verify all the voltages from the power supply. If there are some missing, then you must start to troubleshoot the unit from the point of loss, and go on from there. It is possible that there is a short somewhere, and has damaged the power supply, or some other components failed, and thus caused other types of damage. It is very common in these receivers that the output devices and their respective driver devices, become shorted. In this event, the power supply, and a number of other support components may be damaged. You will have to determine this. -- Jerry G. ========================== "ampapa" wrote in message om... First off I'd like to say, "Hello." to the group. I hope I can gain some knowledge from the group's collective input. I have a Sony STR-DE635 stereo receiver that will not turn on and I would like to investigate into maybe seeing if I can repair it. I found a set of schematics on this site which I believe will definitely help.(http://www.eserviceinfo.com/index.php?what=search2) I'm guessing but I think that the problem is related to the power supply? On p.13 of this .PDF manual it has an A/C and D/C schematic, this receiver has a seperate board for each. I probed the A/C board and found that it has voltage out to the "Digital" board of a little over 12 volts but when I try to test the pins on CNV902 I thought I should be getting appx. 110 A/C but only get appx. 2? CNV902 is a simple 2 wire connector leading directly to a transformer. My common sense is telling me that why would I need a transformaer the size of Kansas for only 2 volts A/C? So, I'm guessing this might have something to do with it? I could be in left field due to my lack of knowledge and inexperience, that's why I'm hoping you guy's/girl's can shed some light. Thanks for any suggestions or hints you can provide. |
#3
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These models often have fuses sort of hidden under a circuit board attached
to the transformer. If these fuses are blown you probably have a blown amp channel. Sometimes just the output transistors for a given channel are bad, sometimes there are other small parts bad. Occasionally a circuit mod is required to lessen the bias at startup. Mark Z. "ampapa" wrote in message om... First off I'd like to say, "Hello." to the group. I hope I can gain some knowledge from the group's collective input. I have a Sony STR-DE635 stereo receiver that will not turn on and I would like to investigate into maybe seeing if I can repair it. I found a set of schematics on this site which I believe will definitely help.(http://www.eserviceinfo.com/index.php?what=search2) I'm guessing but I think that the problem is related to the power supply? On p.13 of this .PDF manual it has an A/C and D/C schematic, this receiver has a seperate board for each. I probed the A/C board and found that it has voltage out to the "Digital" board of a little over 12 volts but when I try to test the pins on CNV902 I thought I should be getting appx. 110 A/C but only get appx. 2? CNV902 is a simple 2 wire connector leading directly to a transformer. My common sense is telling me that why would I need a transformaer the size of Kansas for only 2 volts A/C? So, I'm guessing this might have something to do with it? I could be in left field due to my lack of knowledge and inexperience, that's why I'm hoping you guy's/girl's can shed some light. Thanks for any suggestions or hints you can provide. |
#4
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Jerry,
Thanks for the response. I realize that I am not qualified or have any experience in electronics repair which is why I would deem this as a hobby/experiement and not a profession. Would it be outside the scope of this forum to ask if my logic in the orignal post was corect? Does in fact the transformer expect to see 110v coming in from the A/C board? "I probed the A/C board and found that it has voltage out to the "Digital" board of a little over 12 volts but when I try to test the pins on CNV902 I thought I should be getting appx. 110 A/C but only get appx. 2? CNV902 is a simple 2 wire connector leading directly to a transformer." This in fact is what I am trying to establish. When servicing these sets, the main procedure is to verify all the voltages from the power supply. Thanks for any additional help you can give. AJM, "Jerry G." wrote in message ... These sets can be very difficult to reliably and safely troubleshoot and service. The proper training, service experience, product training, and a solid background in electronics theory would be an asset to do service on these sets. In going by the way you are presenting your questions, I would suggest you give the unit out to an authorized service centre to have an estimate done for you. When servicing these sets, the main procedure is to verify all the voltages from the power supply. If there are some missing, then you must start to troubleshoot the unit from the point of loss, and go on from there. It is possible that there is a short somewhere, and has damaged the power supply, or some other components failed, and thus caused other types of damage. It is very common in these receivers that the output devices and their respective driver devices, become shorted. In this event, the power supply, and a number of other support components may be damaged. You will have to determine this. -- Jerry G. ========================== "ampapa" wrote in message om... First off I'd like to say, "Hello." to the group. I hope I can gain some knowledge from the group's collective input. I have a Sony STR-DE635 stereo receiver that will not turn on and I would like to investigate into maybe seeing if I can repair it. I found a set of schematics on this site which I believe will definitely help.(http://www.eserviceinfo.com/index.php?what=search2) I'm guessing but I think that the problem is related to the power supply? On p.13 of this .PDF manual it has an A/C and D/C schematic, this receiver has a seperate board for each. I probed the A/C board and found that it has voltage out to the "Digital" board of a little over 12 volts but when I try to test the pins on CNV902 I thought I should be getting appx. 110 A/C but only get appx. 2? CNV902 is a simple 2 wire connector leading directly to a transformer. My common sense is telling me that why would I need a transformaer the size of Kansas for only 2 volts A/C? So, I'm guessing this might have something to do with it? I could be in left field due to my lack of knowledge and inexperience, that's why I'm hoping you guy's/girl's can shed some light. Thanks for any suggestions or hints you can provide. |
#5
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Are you saying there would be a fuse physical under the board or just
hidden by another board? This thing has 6 fuses and all checked out fine. If the A/C board isn't putting out the correct voltage to the transformer then certainly it's going to have problems. That's why I was hoping someone would be able to tell by the schematics if in fact the A/C board should be putting out 110, if not then what voltage should I be looking for on CNV902? Thanks. "Mark D. Zacharias" wrote in message ... These models often have fuses sort of hidden under a circuit board attached to the transformer. If these fuses are blown you probably have a blown amp channel. Sometimes just the output transistors for a given channel are bad, sometimes there are other small parts bad. Occasionally a circuit mod is required to lessen the bias at startup. Mark Z. "ampapa" wrote in message om... First off I'd like to say, "Hello." to the group. I hope I can gain some knowledge from the group's collective input. I have a Sony STR-DE635 stereo receiver that will not turn on and I would like to investigate into maybe seeing if I can repair it. I found a set of schematics on this site which I believe will definitely help.(http://www.eserviceinfo.com/index.php?what=search2) I'm guessing but I think that the problem is related to the power supply? On p.13 of this .PDF manual it has an A/C and D/C schematic, this receiver has a seperate board for each. I probed the A/C board and found that it has voltage out to the "Digital" board of a little over 12 volts but when I try to test the pins on CNV902 I thought I should be getting appx. 110 A/C but only get appx. 2? CNV902 is a simple 2 wire connector leading directly to a transformer. My common sense is telling me that why would I need a transformaer the size of Kansas for only 2 volts A/C? So, I'm guessing this might have something to do with it? I could be in left field due to my lack of knowledge and inexperience, that's why I'm hoping you guy's/girl's can shed some light. Thanks for any suggestions or hints you can provide. |
#6
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Sorry if this is a double post.
Mark, are you saying there might be a fuse literaly underneath a circuit board and not necessarily hidden from view by a circuit board? I checked about 5 or 6 fuses in this thing and all checked fine. My biggest problem is that when I read the schematic I can't tell if the transformer is supposed to be getting 110v from the A/C board on CNV902? If it is then I can trace it from there. That's my real dilema. The schematic can be found here (http://www.eserviceinfo.com/index.php?what=search2). Thanks, "Mark D. Zacharias" wrote in message ... These models often have fuses sort of hidden under a circuit board attached to the transformer. If these fuses are blown you probably have a blown amp channel. Sometimes just the output transistors for a given channel are bad, sometimes there are other small parts bad. Occasionally a circuit mod is required to lessen the bias at startup. Mark Z. "ampapa" wrote in message om... First off I'd like to say, "Hello." to the group. I hope I can gain some knowledge from the group's collective input. I have a Sony STR-DE635 stereo receiver that will not turn on and I would like to investigate into maybe seeing if I can repair it. I found a set of schematics on this site which I believe will definitely help.(http://www.eserviceinfo.com/index.php?what=search2) I'm guessing but I think that the problem is related to the power supply? On p.13 of this .PDF manual it has an A/C and D/C schematic, this receiver has a seperate board for each. I probed the A/C board and found that it has voltage out to the "Digital" board of a little over 12 volts but when I try to test the pins on CNV902 I thought I should be getting appx. 110 A/C but only get appx. 2? CNV902 is a simple 2 wire connector leading directly to a transformer. My common sense is telling me that why would I need a transformaer the size of Kansas for only 2 volts A/C? So, I'm guessing this might have something to do with it? I could be in left field due to my lack of knowledge and inexperience, that's why I'm hoping you guy's/girl's can shed some light. Thanks for any suggestions or hints you can provide. |
#7
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If all the fuses are OK, then the power transformer probably isn't getting
voltage from the turn-on relay. Does it click when you press the Power button? CNV902 gets no AC voltage to speak of til this relay fires. (I assume your voltmeter is set to measure AC voltage) Mark Z. "ampapa" wrote in message om... Sorry if this is a double post. Mark, are you saying there might be a fuse literaly underneath a circuit board and not necessarily hidden from view by a circuit board? I checked about 5 or 6 fuses in this thing and all checked fine. My biggest problem is that when I read the schematic I can't tell if the transformer is supposed to be getting 110v from the A/C board on CNV902? If it is then I can trace it from there. That's my real dilema. The schematic can be found here (http://www.eserviceinfo.com/index.php?what=search2). Thanks, "Mark D. Zacharias" wrote in message ... These models often have fuses sort of hidden under a circuit board attached to the transformer. If these fuses are blown you probably have a blown amp channel. Sometimes just the output transistors for a given channel are bad, sometimes there are other small parts bad. Occasionally a circuit mod is required to lessen the bias at startup. Mark Z. "ampapa" wrote in message om... First off I'd like to say, "Hello." to the group. I hope I can gain some knowledge from the group's collective input. I have a Sony STR-DE635 stereo receiver that will not turn on and I would like to investigate into maybe seeing if I can repair it. I found a set of schematics on this site which I believe will definitely help.(http://www.eserviceinfo.com/index.php?what=search2) I'm guessing but I think that the problem is related to the power supply? On p.13 of this .PDF manual it has an A/C and D/C schematic, this receiver has a seperate board for each. I probed the A/C board and found that it has voltage out to the "Digital" board of a little over 12 volts but when I try to test the pins on CNV902 I thought I should be getting appx. 110 A/C but only get appx. 2? CNV902 is a simple 2 wire connector leading directly to a transformer. My common sense is telling me that why would I need a transformaer the size of Kansas for only 2 volts A/C? So, I'm guessing this might have something to do with it? I could be in left field due to my lack of knowledge and inexperience, that's why I'm hoping you guy's/girl's can shed some light. Thanks for any suggestions or hints you can provide. |
#8
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No click when I push the power button and I do have my voltmeter set
to A/C. By looking at the schematic am I correct that the transformer should be seeing appx. 110v? or should I be looking for some other voltage being delivered to the transformer? Also, in order for the A/C board to "enable" the turn-on relay by the on/off switch then I should be seeing voltage coming back from the "Digital" board correct? I see the header that leads to the "Digital" board has 4 legs, GND, 12V, P_OFF and P.RY. Are these designations specific to the industry as to what they represent? Thanks for the help, "Mark D. Zacharias" wrote in message ... If all the fuses are OK, then the power transformer probably isn't getting voltage from the turn-on relay. Does it click when you press the Power button? CNV902 gets no AC voltage to speak of til this relay fires. (I assume your voltmeter is set to measure AC voltage) Mark Z. "ampapa" wrote in message om... Sorry if this is a double post. Mark, are you saying there might be a fuse literaly underneath a circuit board and not necessarily hidden from view by a circuit board? I checked about 5 or 6 fuses in this thing and all checked fine. My biggest problem is that when I read the schematic I can't tell if the transformer is supposed to be getting 110v from the A/C board on CNV902? If it is then I can trace it from there. That's my real dilema. The schematic can be found here (http://www.eserviceinfo.com/index.php?what=search2). Thanks, "Mark D. Zacharias" wrote in message ... These models often have fuses sort of hidden under a circuit board attached to the transformer. If these fuses are blown you probably have a blown amp channel. Sometimes just the output transistors for a given channel are bad, sometimes there are other small parts bad. Occasionally a circuit mod is required to lessen the bias at startup. Mark Z. "ampapa" wrote in message om... First off I'd like to say, "Hello." to the group. I hope I can gain some knowledge from the group's collective input. I have a Sony STR-DE635 stereo receiver that will not turn on and I would like to investigate into maybe seeing if I can repair it. I found a set of schematics on this site which I believe will definitely help.(http://www.eserviceinfo.com/index.php?what=search2) I'm guessing but I think that the problem is related to the power supply? On p.13 of this .PDF manual it has an A/C and D/C schematic, this receiver has a seperate board for each. I probed the A/C board and found that it has voltage out to the "Digital" board of a little over 12 volts but when I try to test the pins on CNV902 I thought I should be getting appx. 110 A/C but only get appx. 2? CNV902 is a simple 2 wire connector leading directly to a transformer. My common sense is telling me that why would I need a transformaer the size of Kansas for only 2 volts A/C? So, I'm guessing this might have something to do with it? I could be in left field due to my lack of knowledge and inexperience, that's why I'm hoping you guy's/girl's can shed some light. Thanks for any suggestions or hints you can provide. |
#9
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Measure from point 12V with respect to ground. I suspect your standby
transformer is bad. Mark Z. "ampapa" wrote in message om... No click when I push the power button and I do have my voltmeter set to A/C. By looking at the schematic am I correct that the transformer should be seeing appx. 110v? or should I be looking for some other voltage being delivered to the transformer? Also, in order for the A/C board to "enable" the turn-on relay by the on/off switch then I should be seeing voltage coming back from the "Digital" board correct? I see the header that leads to the "Digital" board has 4 legs, GND, 12V, P_OFF and P.RY. Are these designations specific to the industry as to what they represent? Thanks for the help, "Mark D. Zacharias" wrote in message ... If all the fuses are OK, then the power transformer probably isn't getting voltage from the turn-on relay. Does it click when you press the Power button? CNV902 gets no AC voltage to speak of til this relay fires. (I assume your voltmeter is set to measure AC voltage) Mark Z. "ampapa" wrote in message om... Sorry if this is a double post. Mark, are you saying there might be a fuse literaly underneath a circuit board and not necessarily hidden from view by a circuit board? I checked about 5 or 6 fuses in this thing and all checked fine. My biggest problem is that when I read the schematic I can't tell if the transformer is supposed to be getting 110v from the A/C board on CNV902? If it is then I can trace it from there. That's my real dilema. The schematic can be found here (http://www.eserviceinfo.com/index.php?what=search2). Thanks, "Mark D. Zacharias" wrote in message ... These models often have fuses sort of hidden under a circuit board attached to the transformer. If these fuses are blown you probably have a blown amp channel. Sometimes just the output transistors for a given channel are bad, sometimes there are other small parts bad. Occasionally a circuit mod is required to lessen the bias at startup. Mark Z. "ampapa" wrote in message om... First off I'd like to say, "Hello." to the group. I hope I can gain some knowledge from the group's collective input. I have a Sony STR-DE635 stereo receiver that will not turn on and I would like to investigate into maybe seeing if I can repair it. I found a set of schematics on this site which I believe will definitely help.(http://www.eserviceinfo.com/index.php?what=search2) I'm guessing but I think that the problem is related to the power supply? On p.13 of this .PDF manual it has an A/C and D/C schematic, this receiver has a seperate board for each. I probed the A/C board and found that it has voltage out to the "Digital" board of a little over 12 volts but when I try to test the pins on CNV902 I thought I should be getting appx. 110 A/C but only get appx. 2? CNV902 is a simple 2 wire connector leading directly to a transformer. My common sense is telling me that why would I need a transformaer the size of Kansas for only 2 volts A/C? So, I'm guessing this might have something to do with it? I could be in left field due to my lack of knowledge and inexperience, that's why I'm hoping you guy's/girl's can shed some light. Thanks for any suggestions or hints you can provide. |
#10
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The "standby transformer" is that T902 on the schematic?
I've got 13.5V on the header that leads to the "Digital" board. "Mark D. Zacharias" wrote in message ... Measure from point 12V with respect to ground. I suspect your standby transformer is bad. Mark Z. "ampapa" wrote in message om... No click when I push the power button and I do have my voltmeter set to A/C. By looking at the schematic am I correct that the transformer should be seeing appx. 110v? or should I be looking for some other voltage being delivered to the transformer? Also, in order for the A/C board to "enable" the turn-on relay by the on/off switch then I should be seeing voltage coming back from the "Digital" board correct? I see the header that leads to the "Digital" board has 4 legs, GND, 12V, P_OFF and P.RY. Are these designations specific to the industry as to what they represent? Thanks for the help, "Mark D. Zacharias" wrote in message ... If all the fuses are OK, then the power transformer probably isn't getting voltage from the turn-on relay. Does it click when you press the Power button? CNV902 gets no AC voltage to speak of til this relay fires. (I assume your voltmeter is set to measure AC voltage) Mark Z. "ampapa" wrote in message om... Sorry if this is a double post. Mark, are you saying there might be a fuse literaly underneath a circuit board and not necessarily hidden from view by a circuit board? I checked about 5 or 6 fuses in this thing and all checked fine. My biggest problem is that when I read the schematic I can't tell if the transformer is supposed to be getting 110v from the A/C board on CNV902? If it is then I can trace it from there. That's my real dilema. The schematic can be found here (http://www.eserviceinfo.com/index.php?what=search2). Thanks, "Mark D. Zacharias" wrote in message ... These models often have fuses sort of hidden under a circuit board attached to the transformer. If these fuses are blown you probably have a blown amp channel. Sometimes just the output transistors for a given channel are bad, sometimes there are other small parts bad. Occasionally a circuit mod is required to lessen the bias at startup. Mark Z. "ampapa" wrote in message om... First off I'd like to say, "Hello." to the group. I hope I can gain some knowledge from the group's collective input. I have a Sony STR-DE635 stereo receiver that will not turn on and I would like to investigate into maybe seeing if I can repair it. I found a set of schematics on this site which I believe will definitely help.(http://www.eserviceinfo.com/index.php?what=search2) I'm guessing but I think that the problem is related to the power supply? On p.13 of this .PDF manual it has an A/C and D/C schematic, this receiver has a seperate board for each. I probed the A/C board and found that it has voltage out to the "Digital" board of a little over 12 volts but when I try to test the pins on CNV902 I thought I should be getting appx. 110 A/C but only get appx. 2? CNV902 is a simple 2 wire connector leading directly to a transformer. My common sense is telling me that why would I need a transformaer the size of Kansas for only 2 volts A/C? So, I'm guessing this might have something to do with it? I could be in left field due to my lack of knowledge and inexperience, that's why I'm hoping you guy's/girl's can shed some light. Thanks for any suggestions or hints you can provide. |
#11
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Well, you need to check the standby voltages on the digital board. Q1205
appears to be a 5 volt source. Mark Z. "ampapa" wrote in message m... The "standby transformer" is that T902 on the schematic? I've got 13.5V on the header that leads to the "Digital" board. "Mark D. Zacharias" wrote in message ... Measure from point 12V with respect to ground. I suspect your standby transformer is bad. Mark Z. "ampapa" wrote in message om... No click when I push the power button and I do have my voltmeter set to A/C. By looking at the schematic am I correct that the transformer should be seeing appx. 110v? or should I be looking for some other voltage being delivered to the transformer? Also, in order for the A/C board to "enable" the turn-on relay by the on/off switch then I should be seeing voltage coming back from the "Digital" board correct? I see the header that leads to the "Digital" board has 4 legs, GND, 12V, P_OFF and P.RY. Are these designations specific to the industry as to what they represent? Thanks for the help, "Mark D. Zacharias" wrote in message ... If all the fuses are OK, then the power transformer probably isn't getting voltage from the turn-on relay. Does it click when you press the Power button? CNV902 gets no AC voltage to speak of til this relay fires. (I assume your voltmeter is set to measure AC voltage) Mark Z. "ampapa" wrote in message om... Sorry if this is a double post. Mark, are you saying there might be a fuse literaly underneath a circuit board and not necessarily hidden from view by a circuit board? I checked about 5 or 6 fuses in this thing and all checked fine. My biggest problem is that when I read the schematic I can't tell if the transformer is supposed to be getting 110v from the A/C board on CNV902? If it is then I can trace it from there. That's my real dilema. The schematic can be found here (http://www.eserviceinfo.com/index.php?what=search2). Thanks, "Mark D. Zacharias" wrote in message ... These models often have fuses sort of hidden under a circuit board attached to the transformer. If these fuses are blown you probably have a blown amp channel. Sometimes just the output transistors for a given channel are bad, sometimes there are other small parts bad. Occasionally a circuit mod is required to lessen the bias at startup. Mark Z. "ampapa" wrote in message om... First off I'd like to say, "Hello." to the group. I hope I can gain some knowledge from the group's collective input. I have a Sony STR-DE635 stereo receiver that will not turn on and I would like to investigate into maybe seeing if I can repair it. I found a set of schematics on this site which I believe will definitely help.(http://www.eserviceinfo.com/index.php?what=search2) I'm guessing but I think that the problem is related to the power supply? On p.13 of this .PDF manual it has an A/C and D/C schematic, this receiver has a seperate board for each. I probed the A/C board and found that it has voltage out to the "Digital" board of a little over 12 volts but when I try to test the pins on CNV902 I thought I should be getting appx. 110 A/C but only get appx. 2? CNV902 is a simple 2 wire connector leading directly to a transformer. My common sense is telling me that why would I need a transformaer the size of Kansas for only 2 volts A/C? So, I'm guessing this might have something to do with it? I could be in left field due to my lack of knowledge and inexperience, that's why I'm hoping you guy's/girl's can shed some light. Thanks for any suggestions or hints you can provide. |
#12
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I've got 3 readings at the transistor Q1205, the center leg 13.53 and
the 2 other legs 6.79 and 6.21 respectively. I think this is wrong, the schematic shows the "base" at 6.5v? "Mark D. Zacharias" wrote in message ... Well, you need to check the standby voltages on the digital board. Q1205 appears to be a 5 volt source. Mark Z. "ampapa" wrote in message m... The "standby transformer" is that T902 on the schematic? I've got 13.5V on the header that leads to the "Digital" board. "Mark D. Zacharias" wrote in message ... Measure from point 12V with respect to ground. I suspect your standby transformer is bad. Mark Z. "ampapa" wrote in message om... No click when I push the power button and I do have my voltmeter set to A/C. By looking at the schematic am I correct that the transformer should be seeing appx. 110v? or should I be looking for some other voltage being delivered to the transformer? Also, in order for the A/C board to "enable" the turn-on relay by the on/off switch then I should be seeing voltage coming back from the "Digital" board correct? I see the header that leads to the "Digital" board has 4 legs, GND, 12V, P_OFF and P.RY. Are these designations specific to the industry as to what they represent? Thanks for the help, "Mark D. Zacharias" wrote in message ... If all the fuses are OK, then the power transformer probably isn't getting voltage from the turn-on relay. Does it click when you press the Power button? CNV902 gets no AC voltage to speak of til this relay fires. (I assume your voltmeter is set to measure AC voltage) Mark Z. "ampapa" wrote in message om... Sorry if this is a double post. Mark, are you saying there might be a fuse literaly underneath a circuit board and not necessarily hidden from view by a circuit board? I checked about 5 or 6 fuses in this thing and all checked fine. My biggest problem is that when I read the schematic I can't tell if the transformer is supposed to be getting 110v from the A/C board on CNV902? If it is then I can trace it from there. That's my real dilema. The schematic can be found here (http://www.eserviceinfo.com/index.php?what=search2). Thanks, "Mark D. Zacharias" wrote in message ... These models often have fuses sort of hidden under a circuit board attached to the transformer. If these fuses are blown you probably have a blown amp channel. Sometimes just the output transistors for a given channel are bad, sometimes there are other small parts bad. Occasionally a circuit mod is required to lessen the bias at startup. Mark Z. "ampapa" wrote in message om... First off I'd like to say, "Hello." to the group. I hope I can gain some knowledge from the group's collective input. I have a Sony STR-DE635 stereo receiver that will not turn on and I would like to investigate into maybe seeing if I can repair it. I found a set of schematics on this site which I believe will definitely help.(http://www.eserviceinfo.com/index.php?what=search2) I'm guessing but I think that the problem is related to the power supply? On p.13 of this .PDF manual it has an A/C and D/C schematic, this receiver has a seperate board for each. I probed the A/C board and found that it has voltage out to the "Digital" board of a little over 12 volts but when I try to test the pins on CNV902 I thought I should be getting appx. 110 A/C but only get appx. 2? CNV902 is a simple 2 wire connector leading directly to a transformer. My common sense is telling me that why would I need a transformaer the size of Kansas for only 2 volts A/C? So, I'm guessing this might have something to do with it? I could be in left field due to my lack of knowledge and inexperience, that's why I'm hoping you guy's/girl's can shed some light. Thanks for any suggestions or hints you can provide. |
#13
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I've got 3 readings at the transistor Q1205, the center leg 13.53 and
the 2 other legs 6.79 and 6.21 respectively. I think this is wrong, the schematic shows the "base" at 6.5v? "Mark D. Zacharias" wrote in message ... Well, you need to check the standby voltages on the digital board. Q1205 appears to be a 5 volt source. Mark Z. "ampapa" wrote in message m... The "standby transformer" is that T902 on the schematic? I've got 13.5V on the header that leads to the "Digital" board. "Mark D. Zacharias" wrote in message ... Measure from point 12V with respect to ground. I suspect your standby transformer is bad. Mark Z. "ampapa" wrote in message om... No click when I push the power button and I do have my voltmeter set to A/C. By looking at the schematic am I correct that the transformer should be seeing appx. 110v? or should I be looking for some other voltage being delivered to the transformer? Also, in order for the A/C board to "enable" the turn-on relay by the on/off switch then I should be seeing voltage coming back from the "Digital" board correct? I see the header that leads to the "Digital" board has 4 legs, GND, 12V, P_OFF and P.RY. Are these designations specific to the industry as to what they represent? Thanks for the help, "Mark D. Zacharias" wrote in message ... If all the fuses are OK, then the power transformer probably isn't getting voltage from the turn-on relay. Does it click when you press the Power button? CNV902 gets no AC voltage to speak of til this relay fires. (I assume your voltmeter is set to measure AC voltage) Mark Z. "ampapa" wrote in message om... Sorry if this is a double post. Mark, are you saying there might be a fuse literaly underneath a circuit board and not necessarily hidden from view by a circuit board? I checked about 5 or 6 fuses in this thing and all checked fine. My biggest problem is that when I read the schematic I can't tell if the transformer is supposed to be getting 110v from the A/C board on CNV902? If it is then I can trace it from there. That's my real dilema. The schematic can be found here (http://www.eserviceinfo.com/index.php?what=search2). Thanks, "Mark D. Zacharias" wrote in message ... These models often have fuses sort of hidden under a circuit board attached to the transformer. If these fuses are blown you probably have a blown amp channel. Sometimes just the output transistors for a given channel are bad, sometimes there are other small parts bad. Occasionally a circuit mod is required to lessen the bias at startup. Mark Z. "ampapa" wrote in message om... First off I'd like to say, "Hello." to the group. I hope I can gain some knowledge from the group's collective input. I have a Sony STR-DE635 stereo receiver that will not turn on and I would like to investigate into maybe seeing if I can repair it. I found a set of schematics on this site which I believe will definitely help.(http://www.eserviceinfo.com/index.php?what=search2) I'm guessing but I think that the problem is related to the power supply? On p.13 of this .PDF manual it has an A/C and D/C schematic, this receiver has a seperate board for each. I probed the A/C board and found that it has voltage out to the "Digital" board of a little over 12 volts but when I try to test the pins on CNV902 I thought I should be getting appx. 110 A/C but only get appx. 2? CNV902 is a simple 2 wire connector leading directly to a transformer. My common sense is telling me that why would I need a transformaer the size of Kansas for only 2 volts A/C? So, I'm guessing this might have something to do with it? I could be in left field due to my lack of knowledge and inexperience, that's why I'm hoping you guy's/girl's can shed some light. Thanks for any suggestions or hints you can provide. |
#14
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I'd say that's close enough. You're going to have to see that the "5V" line
makes it to the microprocessor, and at this point you're going to have to evaluate the reset line to the micro. Should toggle from ground to 5V when you plug in the cord. Mark Z. "ampapa" wrote in message m... I've got 3 readings at the transistor Q1205, the center leg 13.53 and the 2 other legs 6.79 and 6.21 respectively. I think this is wrong, the schematic shows the "base" at 6.5v? "Mark D. Zacharias" wrote in message ... Well, you need to check the standby voltages on the digital board. Q1205 appears to be a 5 volt source. Mark Z. "ampapa" wrote in message m... The "standby transformer" is that T902 on the schematic? I've got 13.5V on the header that leads to the "Digital" board. "Mark D. Zacharias" wrote in message ... Measure from point 12V with respect to ground. I suspect your standby transformer is bad. Mark Z. "ampapa" wrote in message om... No click when I push the power button and I do have my voltmeter set to A/C. By looking at the schematic am I correct that the transformer should be seeing appx. 110v? or should I be looking for some other voltage being delivered to the transformer? Also, in order for the A/C board to "enable" the turn-on relay by the on/off switch then I should be seeing voltage coming back from the "Digital" board correct? I see the header that leads to the "Digital" board has 4 legs, GND, 12V, P_OFF and P.RY. Are these designations specific to the industry as to what they represent? Thanks for the help, "Mark D. Zacharias" wrote in message ... If all the fuses are OK, then the power transformer probably isn't getting voltage from the turn-on relay. Does it click when you press the Power button? CNV902 gets no AC voltage to speak of til this relay fires. (I assume your voltmeter is set to measure AC voltage) Mark Z. "ampapa" wrote in message om... Sorry if this is a double post. Mark, are you saying there might be a fuse literaly underneath a circuit board and not necessarily hidden from view by a circuit board? I checked about 5 or 6 fuses in this thing and all checked fine. My biggest problem is that when I read the schematic I can't tell if the transformer is supposed to be getting 110v from the A/C board on CNV902? If it is then I can trace it from there. That's my real dilema. The schematic can be found here (http://www.eserviceinfo.com/index.php?what=search2). Thanks, "Mark D. Zacharias" wrote in message ... These models often have fuses sort of hidden under a circuit board attached to the transformer. If these fuses are blown you probably have a blown amp channel. Sometimes just the output transistors for a given channel are bad, sometimes there are other small parts bad. Occasionally a circuit mod is required to lessen the bias at startup. Mark Z. "ampapa" wrote in message om... First off I'd like to say, "Hello." to the group. I hope I can gain some knowledge from the group's collective input. I have a Sony STR-DE635 stereo receiver that will not turn on and I would like to investigate into maybe seeing if I can repair it. I found a set of schematics on this site which I believe will definitely help.(http://www.eserviceinfo.com/index.php?what=search2) I'm guessing but I think that the problem is related to the power supply? On p.13 of this .PDF manual it has an A/C and D/C schematic, this receiver has a seperate board for each. I probed the A/C board and found that it has voltage out to the "Digital" board of a little over 12 volts but when I try to test the pins on CNV902 I thought I should be getting appx. 110 A/C but only get appx. 2? CNV902 is a simple 2 wire connector leading directly to a transformer. My common sense is telling me that why would I need a transformaer the size of Kansas for only 2 volts A/C? So, I'm guessing this might have something to do with it? I could be in left field due to my lack of knowledge and inexperience, that's why I'm hoping you guy's/girl's can shed some light. Thanks for any suggestions or hints you can provide. |
#15
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P.S.
If there's any history on this that I should know, now is definitely the time to say. For example if there was a lightning strike involved. Mark Z. "Mark D. Zacharias" wrote in message ... I'd say that's close enough. You're going to have to see that the "5V" line makes it to the microprocessor, and at this point you're going to have to evaluate the reset line to the micro. Should toggle from ground to 5V when you plug in the cord. Mark Z. "ampapa" wrote in message m... I've got 3 readings at the transistor Q1205, the center leg 13.53 and the 2 other legs 6.79 and 6.21 respectively. I think this is wrong, the schematic shows the "base" at 6.5v? "Mark D. Zacharias" wrote in message ... Well, you need to check the standby voltages on the digital board. Q1205 appears to be a 5 volt source. Mark Z. "ampapa" wrote in message m... The "standby transformer" is that T902 on the schematic? I've got 13.5V on the header that leads to the "Digital" board. "Mark D. Zacharias" wrote in message ... Measure from point 12V with respect to ground. I suspect your standby transformer is bad. Mark Z. "ampapa" wrote in message om... No click when I push the power button and I do have my voltmeter set to A/C. By looking at the schematic am I correct that the transformer should be seeing appx. 110v? or should I be looking for some other voltage being delivered to the transformer? Also, in order for the A/C board to "enable" the turn-on relay by the on/off switch then I should be seeing voltage coming back from the "Digital" board correct? I see the header that leads to the "Digital" board has 4 legs, GND, 12V, P_OFF and P.RY. Are these designations specific to the industry as to what they represent? Thanks for the help, "Mark D. Zacharias" wrote in message ... If all the fuses are OK, then the power transformer probably isn't getting voltage from the turn-on relay. Does it click when you press the Power button? CNV902 gets no AC voltage to speak of til this relay fires. (I assume your voltmeter is set to measure AC voltage) Mark Z. "ampapa" wrote in message om... Sorry if this is a double post. Mark, are you saying there might be a fuse literaly underneath a circuit board and not necessarily hidden from view by a circuit board? I checked about 5 or 6 fuses in this thing and all checked fine. My biggest problem is that when I read the schematic I can't tell if the transformer is supposed to be getting 110v from the A/C board on CNV902? If it is then I can trace it from there. That's my real dilema. The schematic can be found here (http://www.eserviceinfo.com/index.php?what=search2). Thanks, "Mark D. Zacharias" wrote in message ... These models often have fuses sort of hidden under a circuit board attached to the transformer. If these fuses are blown you probably have a blown amp channel. Sometimes just the output transistors for a given channel are bad, sometimes there are other small parts bad. Occasionally a circuit mod is required to lessen the bias at startup. Mark Z. "ampapa" wrote in message om... First off I'd like to say, "Hello." to the group. I hope I can gain some knowledge from the group's collective input. I have a Sony STR-DE635 stereo receiver that will not turn on and I would like to investigate into maybe seeing if I can repair it. I found a set of schematics on this site which I believe will definitely help.(http://www.eserviceinfo.com/index.php?what=search2) I'm guessing but I think that the problem is related to the power supply? On p.13 of this .PDF manual it has an A/C and D/C schematic, this receiver has a seperate board for each. I probed the A/C board and found that it has voltage out to the "Digital" board of a little over 12 volts but when I try to test the pins on CNV902 I thought I should be getting appx. 110 A/C but only get appx. 2? CNV902 is a simple 2 wire connector leading directly to a transformer. My common sense is telling me that why would I need a transformaer the size of Kansas for only 2 volts A/C? So, I'm guessing this might have something to do with it? I could be in left field due to my lack of knowledge and inexperience, that's why I'm hoping you guy's/girl's can shed some light. Thanks for any suggestions or hints you can provide. |
#16
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Mark, thanks for your help.
"microprocessor" are you referring to the 8 pin IC1206? I'm a bit confused at Q1205 the base reading is 13.53v, why? Shouldn't that be more like 6.5v? One thing that keeps bugging me is the P_RY leg from the A/C board. Is this the return leg to the transformer on the A/C board? It's currently reading 0v. Also, before I flipped the "Digital" board over I noticed some red crayon looking markings around the 2 IC's 1205 and 1207. When I flipped the board over it looks as though they've been soldered on? I don't think this has been worked on, so I thought I would make mention seeing as we were in the area and it looked strange. "Mark D. Zacharias" wrote in message ... I'd say that's close enough. You're going to have to see that the "5V" line makes it to the microprocessor, and at this point you're going to have to evaluate the reset line to the micro. Should toggle from ground to 5V when you plug in the cord. Mark Z. "ampapa" wrote in message m... I've got 3 readings at the transistor Q1205, the center leg 13.53 and the 2 other legs 6.79 and 6.21 respectively. I think this is wrong, the schematic shows the "base" at 6.5v? "Mark D. Zacharias" wrote in message ... Well, you need to check the standby voltages on the digital board. Q1205 appears to be a 5 volt source. Mark Z. "ampapa" wrote in message m... The "standby transformer" is that T902 on the schematic? I've got 13.5V on the header that leads to the "Digital" board. "Mark D. Zacharias" wrote in message ... Measure from point 12V with respect to ground. I suspect your standby transformer is bad. Mark Z. "ampapa" wrote in message om... No click when I push the power button and I do have my voltmeter set to A/C. By looking at the schematic am I correct that the transformer should be seeing appx. 110v? or should I be looking for some other voltage being delivered to the transformer? Also, in order for the A/C board to "enable" the turn-on relay by the on/off switch then I should be seeing voltage coming back from the "Digital" board correct? I see the header that leads to the "Digital" board has 4 legs, GND, 12V, P_OFF and P.RY. Are these designations specific to the industry as to what they represent? Thanks for the help, "Mark D. Zacharias" wrote in message ... If all the fuses are OK, then the power transformer probably isn't getting voltage from the turn-on relay. Does it click when you press the Power button? CNV902 gets no AC voltage to speak of til this relay fires. (I assume your voltmeter is set to measure AC voltage) Mark Z. "ampapa" wrote in message om... Sorry if this is a double post. Mark, are you saying there might be a fuse literaly underneath a circuit board and not necessarily hidden from view by a circuit board? I checked about 5 or 6 fuses in this thing and all checked fine. My biggest problem is that when I read the schematic I can't tell if the transformer is supposed to be getting 110v from the A/C board on CNV902? If it is then I can trace it from there. That's my real dilema. The schematic can be found here (http://www.eserviceinfo.com/index.php?what=search2). Thanks, "Mark D. Zacharias" wrote in message ... These models often have fuses sort of hidden under a circuit board attached to the transformer. If these fuses are blown you probably have a blown amp channel. Sometimes just the output transistors for a given channel are bad, sometimes there are other small parts bad. Occasionally a circuit mod is required to lessen the bias at startup. Mark Z. "ampapa" wrote in message om... First off I'd like to say, "Hello." to the group. I hope I can gain some knowledge from the group's collective input. I have a Sony STR-DE635 stereo receiver that will not turn on and I would like to investigate into maybe seeing if I can repair it. I found a set of schematics on this site which I believe will definitely help.(http://www.eserviceinfo.com/index.php?what=search2) I'm guessing but I think that the problem is related to the power supply? On p.13 of this .PDF manual it has an A/C and D/C schematic, this receiver has a seperate board for each. I probed the A/C board and found that it has voltage out to the "Digital" board of a little over 12 volts but when I try to test the pins on CNV902 I thought I should be getting appx. 110 A/C but only get appx. 2? CNV902 is a simple 2 wire connector leading directly to a transformer. My common sense is telling me that why would I need a transformaer the size of Kansas for only 2 volts A/C? So, I'm guessing this might have something to do with it? I could be in left field due to my lack of knowledge and inexperience, that's why I'm hoping you guy's/girl's can shed some light. Thanks for any suggestions or hints you can provide. |
#17
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comments inserted.
"ampapa" wrote in message om... Mark, thanks for your help. "microprocessor" are you referring to the 8 pin IC1206? It does appear that the reset pulse comes from IC 1206 pin 8. The microprocessor is IC 1201. I'm a bit confused at Q1205 the base reading is 13.53v, why? Shouldn't that be more like 6.5v? This is a somewhat unusual circuit,but that voltage certainly looks wrong. The transistor Q1205 might be shorted, and / or IC 1206 might be bad. Unfortunately, if this places 12 to 13 volts at the cathode of D1211 (1208) the microprocessor may very well be fried. One thing that keeps bugging me is the P_RY leg from the A/C board. Is this the return leg to the transformer on the A/C board? It's currently reading 0v. This line would probably toggle to 5v or so to turn on the relay if the receiver were working properly. It's not, so you see nothing here. Also, before I flipped the "Digital" board over I noticed some red crayon looking markings around the 2 IC's 1205 and 1207. When I flipped the board over it looks as though they've been soldered on? I don't think this has been worked on, so I thought I would make mention seeing as we were in the area and it looked strange. Maybe some prior factory rework. I don't think I'd worry about it at this point, unless the work looks really sloppy or something's obviously wrong, like a wire hanging and shorting against something, etc. snip This repair is going nowhere fast. It would be nice to have another digital board to sub. Oh, well. Mark Z. |
#18
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Mark,
I spoke with my friend this afternonn and this was a refurb from the factory his sister used to work for a Sony call center, but until recently the receiver was working fine. He was having a on/off issue, no lightning strike. I mistyped earlier the 2 IC's that looked like they were replaced are IC1205 and IC1501 as well as D1207 and D1206. I tested the diodes with my DMM it has a diode test and they appear to be O.K. (tested one direction then flipped leads). I'm not sure how to test the IC's? I took some readings on the 2 IC's (IC1025 and IC1501) and was getting ..25v on leg 1 on both and 0v on the other legs. I also checked IC1206 and here is how it layed out, definitely out of wack... 8 - 1.6v 7 - 1.25v 6 - 6.76v 5 - 0 4 - .35 3 - 1.83 2 - 2.37 1 - 13.53 I wasn't sure what to test on IC1201 did you want me to look at the reset pin 90 for 5v? My biggest understanding issue is how do I determine the flow on the schematic? "This repair is going nowhere fast. It would be nice to have another digital board to sub." My posts take forever to show up on the forum is there a way to speed it up??? As far as another board I don't think I can find one? do you know anyone selling them, cost, etc. AJM, "Mark D. Zacharias" wrote in message ... P.S. If there's any history on this that I should know, now is definitely the time to say. For example if there was a lightning strike involved. Mark Z. "Mark D. Zacharias" wrote in message ... I'd say that's close enough. You're going to have to see that the "5V" line makes it to the microprocessor, and at this point you're going to have to evaluate the reset line to the micro. Should toggle from ground to 5V when you plug in the cord. Mark Z. "ampapa" wrote in message m... I've got 3 readings at the transistor Q1205, the center leg 13.53 and the 2 other legs 6.79 and 6.21 respectively. I think this is wrong, the schematic shows the "base" at 6.5v? "Mark D. Zacharias" wrote in message ... Well, you need to check the standby voltages on the digital board. Q1205 appears to be a 5 volt source. Mark Z. "ampapa" wrote in message m... The "standby transformer" is that T902 on the schematic? I've got 13.5V on the header that leads to the "Digital" board. "Mark D. Zacharias" wrote in message ... Measure from point 12V with respect to ground. I suspect your standby transformer is bad. Mark Z. "ampapa" wrote in message om... No click when I push the power button and I do have my voltmeter set to A/C. By looking at the schematic am I correct that the transformer should be seeing appx. 110v? or should I be looking for some other voltage being delivered to the transformer? Also, in order for the A/C board to "enable" the turn-on relay by the on/off switch then I should be seeing voltage coming back from the "Digital" board correct? I see the header that leads to the "Digital" board has 4 legs, GND, 12V, P_OFF and P.RY. Are these designations specific to the industry as to what they represent? Thanks for the help, "Mark D. Zacharias" wrote in message ... If all the fuses are OK, then the power transformer probably isn't getting voltage from the turn-on relay. Does it click when you press the Power button? CNV902 gets no AC voltage to speak of til this relay fires. (I assume your voltmeter is set to measure AC voltage) Mark Z. "ampapa" wrote in message om... Sorry if this is a double post. Mark, are you saying there might be a fuse literaly underneath a circuit board and not necessarily hidden from view by a circuit board? I checked about 5 or 6 fuses in this thing and all checked fine. My biggest problem is that when I read the schematic I can't tell if the transformer is supposed to be getting 110v from the A/C board on CNV902? If it is then I can trace it from there. That's my real dilema. The schematic can be found here (http://www.eserviceinfo.com/index.php?what=search2). Thanks, "Mark D. Zacharias" wrote in message ... These models often have fuses sort of hidden under a circuit board attached to the transformer. If these fuses are blown you probably have a blown amp channel. Sometimes just the output transistors for a given channel are bad, sometimes there are other small parts bad. Occasionally a circuit mod is required to lessen the bias at startup. Mark Z. "ampapa" wrote in message om... First off I'd like to say, "Hello." to the group. I hope I can gain some knowledge from the group's collective input. I have a Sony STR-DE635 stereo receiver that will not turn on and I would like to investigate into maybe seeing if I can repair it. I found a set of schematics on this site which I believe will definitely help.(http://www.eserviceinfo.com/index.php?what=search2) I'm guessing but I think that the problem is related to the power supply? On p.13 of this .PDF manual it has an A/C and D/C schematic, this receiver has a seperate board for each. I probed the A/C board and found that it has voltage out to the "Digital" board of a little over 12 volts but when I try to test the pins on CNV902 I thought I should be getting appx. 110 A/C but only get appx. 2? CNV902 is a simple 2 wire connector leading directly to a transformer. My common sense is telling me that why would I need a transformaer the size of Kansas for only 2 volts A/C? So, I'm guessing this might have something to do with it? I could be in left field due to my lack of knowledge and inexperience, that's why I'm hoping you guy's/girl's can shed some light. Thanks for any suggestions or hints you can provide. |
#19
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I'm going to digest this for a bit and will post back later.
Meanwhile, if you're posting through Google, they only add posts once or twice a day. Mark Z. "ampapa" wrote in message om... Mark, I spoke with my friend this afternonn and this was a refurb from the factory his sister used to work for a Sony call center, but until recently the receiver was working fine. He was having a on/off issue, no lightning strike. I mistyped earlier the 2 IC's that looked like they were replaced are IC1205 and IC1501 as well as D1207 and D1206. I tested the diodes with my DMM it has a diode test and they appear to be O.K. (tested one direction then flipped leads). I'm not sure how to test the IC's? I took some readings on the 2 IC's (IC1025 and IC1501) and was getting .25v on leg 1 on both and 0v on the other legs. I also checked IC1206 and here is how it layed out, definitely out of wack... 8 - 1.6v 7 - 1.25v 6 - 6.76v 5 - 0 4 - .35 3 - 1.83 2 - 2.37 1 - 13.53 I wasn't sure what to test on IC1201 did you want me to look at the reset pin 90 for 5v? My biggest understanding issue is how do I determine the flow on the schematic? "This repair is going nowhere fast. It would be nice to have another digital board to sub." My posts take forever to show up on the forum is there a way to speed it up??? As far as another board I don't think I can find one? do you know anyone selling them, cost, etc. AJM, "Mark D. Zacharias" wrote in message ... P.S. If there's any history on this that I should know, now is definitely the time to say. For example if there was a lightning strike involved. Mark Z. "Mark D. Zacharias" wrote in message ... I'd say that's close enough. You're going to have to see that the "5V" line makes it to the microprocessor, and at this point you're going to have to evaluate the reset line to the micro. Should toggle from ground to 5V when you plug in the cord. Mark Z. "ampapa" wrote in message m... I've got 3 readings at the transistor Q1205, the center leg 13.53 and the 2 other legs 6.79 and 6.21 respectively. I think this is wrong, the schematic shows the "base" at 6.5v? "Mark D. Zacharias" wrote in message ... Well, you need to check the standby voltages on the digital board. Q1205 appears to be a 5 volt source. Mark Z. "ampapa" wrote in message m... The "standby transformer" is that T902 on the schematic? I've got 13.5V on the header that leads to the "Digital" board. "Mark D. Zacharias" wrote in message ... Measure from point 12V with respect to ground. I suspect your standby transformer is bad. Mark Z. "ampapa" wrote in message om... No click when I push the power button and I do have my voltmeter set to A/C. By looking at the schematic am I correct that the transformer should be seeing appx. 110v? or should I be looking for some other voltage being delivered to the transformer? Also, in order for the A/C board to "enable" the turn-on relay by the on/off switch then I should be seeing voltage coming back from the "Digital" board correct? I see the header that leads to the "Digital" board has 4 legs, GND, 12V, P_OFF and P.RY. Are these designations specific to the industry as to what they represent? Thanks for the help, "Mark D. Zacharias" wrote in message ... If all the fuses are OK, then the power transformer probably isn't getting voltage from the turn-on relay. Does it click when you press the Power button? CNV902 gets no AC voltage to speak of til this relay fires. (I assume your voltmeter is set to measure AC voltage) Mark Z. "ampapa" wrote in message om... Sorry if this is a double post. Mark, are you saying there might be a fuse literaly underneath a circuit board and not necessarily hidden from view by a circuit board? I checked about 5 or 6 fuses in this thing and all checked fine. My biggest problem is that when I read the schematic I can't tell if the transformer is supposed to be getting 110v from the A/C board on CNV902? If it is then I can trace it from there. That's my real dilema. The schematic can be found here (http://www.eserviceinfo.com/index.php?what=search2). Thanks, "Mark D. Zacharias" wrote in message ... These models often have fuses sort of hidden under a circuit board attached to the transformer. If these fuses are blown you probably have a blown amp channel. Sometimes just the output transistors for a given channel are bad, sometimes there are other small parts bad. Occasionally a circuit mod is required to lessen the bias at startup. Mark Z. "ampapa" wrote in message om... First off I'd like to say, "Hello." to the group. I hope I can gain some knowledge from the group's collective input. I have a Sony STR-DE635 stereo receiver that will not turn on and I would like to investigate into maybe seeing if I can repair it. I found a set of schematics on this site which I believe will definitely help.(http://www.eserviceinfo.com/index.php?what=search2) I'm guessing but I think that the problem is related to the power supply? On p.13 of this .PDF manual it has an A/C and D/C schematic, this receiver has a seperate board for each. I probed the A/C board and found that it has voltage out to the "Digital" board of a little over 12 volts but when I try to test the pins on CNV902 I thought I should be getting appx. 110 A/C but only get appx. 2? CNV902 is a simple 2 wire connector leading directly to a transformer. My common sense is telling me that why would I need a transformaer the size of Kansas for only 2 volts A/C? So, I'm guessing this might have something to do with it? I could be in left field due to my lack of knowledge and inexperience, that's why I'm hoping you guy's/girl's can shed some light. Thanks for any suggestions or hints you can provide. |
#20
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How can I post quicker so we can respond faster?
"Mark D. Zacharias" wrote in message ... I'm going to digest this for a bit and will post back later. Meanwhile, if you're posting through Google, they only add posts once or twice a day. Mark Z. "ampapa" wrote in message om... Mark, I spoke with my friend this afternonn and this was a refurb from the factory his sister used to work for a Sony call center, but until recently the receiver was working fine. He was having a on/off issue, no lightning strike. I mistyped earlier the 2 IC's that looked like they were replaced are IC1205 and IC1501 as well as D1207 and D1206. I tested the diodes with my DMM it has a diode test and they appear to be O.K. (tested one direction then flipped leads). I'm not sure how to test the IC's? I took some readings on the 2 IC's (IC1025 and IC1501) and was getting .25v on leg 1 on both and 0v on the other legs. I also checked IC1206 and here is how it layed out, definitely out of wack... 8 - 1.6v 7 - 1.25v 6 - 6.76v 5 - 0 4 - .35 3 - 1.83 2 - 2.37 1 - 13.53 I wasn't sure what to test on IC1201 did you want me to look at the reset pin 90 for 5v? My biggest understanding issue is how do I determine the flow on the schematic? "This repair is going nowhere fast. It would be nice to have another digital board to sub." My posts take forever to show up on the forum is there a way to speed it up??? As far as another board I don't think I can find one? do you know anyone selling them, cost, etc. AJM, "Mark D. Zacharias" wrote in message ... P.S. If there's any history on this that I should know, now is definitely the time to say. For example if there was a lightning strike involved. Mark Z. "Mark D. Zacharias" wrote in message ... I'd say that's close enough. You're going to have to see that the "5V" line makes it to the microprocessor, and at this point you're going to have to evaluate the reset line to the micro. Should toggle from ground to 5V when you plug in the cord. Mark Z. "ampapa" wrote in message m... I've got 3 readings at the transistor Q1205, the center leg 13.53 and the 2 other legs 6.79 and 6.21 respectively. I think this is wrong, the schematic shows the "base" at 6.5v? "Mark D. Zacharias" wrote in message ... Well, you need to check the standby voltages on the digital board. Q1205 appears to be a 5 volt source. Mark Z. "ampapa" wrote in message m... The "standby transformer" is that T902 on the schematic? I've got 13.5V on the header that leads to the "Digital" board. "Mark D. Zacharias" wrote in message ... Measure from point 12V with respect to ground. I suspect your standby transformer is bad. Mark Z. "ampapa" wrote in message om... No click when I push the power button and I do have my voltmeter set to A/C. By looking at the schematic am I correct that the transformer should be seeing appx. 110v? or should I be looking for some other voltage being delivered to the transformer? Also, in order for the A/C board to "enable" the turn-on relay by the on/off switch then I should be seeing voltage coming back from the "Digital" board correct? I see the header that leads to the "Digital" board has 4 legs, GND, 12V, P_OFF and P.RY. Are these designations specific to the industry as to what they represent? Thanks for the help, "Mark D. Zacharias" wrote in message ... If all the fuses are OK, then the power transformer probably isn't getting voltage from the turn-on relay. Does it click when you press the Power button? CNV902 gets no AC voltage to speak of til this relay fires. (I assume your voltmeter is set to measure AC voltage) Mark Z. "ampapa" wrote in message om... Sorry if this is a double post. Mark, are you saying there might be a fuse literaly underneath a circuit board and not necessarily hidden from view by a circuit board? I checked about 5 or 6 fuses in this thing and all checked fine. My biggest problem is that when I read the schematic I can't tell if the transformer is supposed to be getting 110v from the A/C board on CNV902? If it is then I can trace it from there. That's my real dilema. The schematic can be found here (http://www.eserviceinfo.com/index.php?what=search2). Thanks, "Mark D. Zacharias" wrote in message ... These models often have fuses sort of hidden under a circuit board attached to the transformer. If these fuses are blown you probably have a blown amp channel. Sometimes just the output transistors for a given channel are bad, sometimes there are other small parts bad. Occasionally a circuit mod is required to lessen the bias at startup. Mark Z. "ampapa" wrote in message om... First off I'd like to say, "Hello." to the group. I hope I can gain some knowledge from the group's collective input. I have a Sony STR-DE635 stereo receiver that will not turn on and I would like to investigate into maybe seeing if I can repair it. I found a set of schematics on this site which I believe will definitely help.(http://www.eserviceinfo.com/index.php?what=search2) I'm guessing but I think that the problem is related to the power supply? On p.13 of this .PDF manual it has an A/C and D/C schematic, this receiver has a seperate board for each. I probed the A/C board and found that it has voltage out to the "Digital" board of a little over 12 volts but when I try to test the pins on CNV902 I thought I should be getting appx. 110 A/C but only get appx. 2? CNV902 is a simple 2 wire connector leading directly to a transformer. My common sense is telling me that why would I need a transformaer the size of Kansas for only 2 volts A/C? So, I'm guessing this might have something to do with it? I could be in left field due to my lack of knowledge and inexperience, that's why I'm hoping you guy's/girl's can shed some light. Thanks for any suggestions or hints you can provide. |
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I'm having a bit of frustration tracing the source of the 8.3 volts feeding
IC 1205. It's clear that this is a standby voltage, since it supplies the IR receiver and the front panel display driver IC, which in turn pipes the turn-on commands and front panel controls to the main micro on your digital board. This voltage loops through to page 46 (Point I) pin 6 but exactly where it branches off from there is anybody's guess. You see only the + and - 15 volt lines branching off. The 8 v seems to have dropped off the map. I'm running out of time right now, got to get to work. I'll look at it some more later and re-post. Later. Mark Z. "ampapa" wrote in message om... Mark, I spoke with my friend this afternonn and this was a refurb from the factory his sister used to work for a Sony call center, but until recently the receiver was working fine. He was having a on/off issue, no lightning strike. I mistyped earlier the 2 IC's that looked like they were replaced are IC1205 and IC1501 as well as D1207 and D1206. I tested the diodes with my DMM it has a diode test and they appear to be O.K. (tested one direction then flipped leads). I'm not sure how to test the IC's? I took some readings on the 2 IC's (IC1025 and IC1501) and was getting .25v on leg 1 on both and 0v on the other legs. I also checked IC1206 and here is how it layed out, definitely out of wack... 8 - 1.6v 7 - 1.25v 6 - 6.76v 5 - 0 4 - .35 3 - 1.83 2 - 2.37 1 - 13.53 I wasn't sure what to test on IC1201 did you want me to look at the reset pin 90 for 5v? My biggest understanding issue is how do I determine the flow on the schematic? "This repair is going nowhere fast. It would be nice to have another digital board to sub." My posts take forever to show up on the forum is there a way to speed it up??? As far as another board I don't think I can find one? do you know anyone selling them, cost, etc. AJM, "Mark D. Zacharias" wrote in message ... P.S. If there's any history on this that I should know, now is definitely the time to say. For example if there was a lightning strike involved. Mark Z. "Mark D. Zacharias" wrote in message ... I'd say that's close enough. You're going to have to see that the "5V" line makes it to the microprocessor, and at this point you're going to have to evaluate the reset line to the micro. Should toggle from ground to 5V when you plug in the cord. Mark Z. "ampapa" wrote in message m... I've got 3 readings at the transistor Q1205, the center leg 13.53 and the 2 other legs 6.79 and 6.21 respectively. I think this is wrong, the schematic shows the "base" at 6.5v? "Mark D. Zacharias" wrote in message ... Well, you need to check the standby voltages on the digital board. Q1205 appears to be a 5 volt source. Mark Z. "ampapa" wrote in message m... The "standby transformer" is that T902 on the schematic? I've got 13.5V on the header that leads to the "Digital" board. "Mark D. Zacharias" wrote in message ... Measure from point 12V with respect to ground. I suspect your standby transformer is bad. Mark Z. "ampapa" wrote in message om... No click when I push the power button and I do have my voltmeter set to A/C. By looking at the schematic am I correct that the transformer should be seeing appx. 110v? or should I be looking for some other voltage being delivered to the transformer? Also, in order for the A/C board to "enable" the turn-on relay by the on/off switch then I should be seeing voltage coming back from the "Digital" board correct? I see the header that leads to the "Digital" board has 4 legs, GND, 12V, P_OFF and P.RY. Are these designations specific to the industry as to what they represent? Thanks for the help, "Mark D. Zacharias" wrote in message ... If all the fuses are OK, then the power transformer probably isn't getting voltage from the turn-on relay. Does it click when you press the Power button? CNV902 gets no AC voltage to speak of til this relay fires. (I assume your voltmeter is set to measure AC voltage) Mark Z. "ampapa" wrote in message om... Sorry if this is a double post. Mark, are you saying there might be a fuse literaly underneath a circuit board and not necessarily hidden from view by a circuit board? I checked about 5 or 6 fuses in this thing and all checked fine. My biggest problem is that when I read the schematic I can't tell if the transformer is supposed to be getting 110v from the A/C board on CNV902? If it is then I can trace it from there. That's my real dilema. The schematic can be found here (http://www.eserviceinfo.com/index.php?what=search2). Thanks, "Mark D. Zacharias" wrote in message ... These models often have fuses sort of hidden under a circuit board attached to the transformer. If these fuses are blown you probably have a blown amp channel. Sometimes just the output transistors for a given channel are bad, sometimes there are other small parts bad. Occasionally a circuit mod is required to lessen the bias at startup. Mark Z. "ampapa" wrote in message om... First off I'd like to say, "Hello." to the group. I hope I can gain some knowledge from the group's collective input. I have a Sony STR-DE635 stereo receiver that will not turn on and I would like to investigate into maybe seeing if I can repair it. I found a set of schematics on this site which I believe will definitely help.(http://www.eserviceinfo.com/index.php?what=search2) I'm guessing but I think that the problem is related to the power supply? On p.13 of this .PDF manual it has an A/C and D/C schematic, this receiver has a seperate board for each. I probed the A/C board and found that it has voltage out to the "Digital" board of a little over 12 volts but when I try to test the pins on CNV902 I thought I should be getting appx. 110 A/C but only get appx. 2? CNV902 is a simple 2 wire connector leading directly to a transformer. My common sense is telling me that why would I need a transformaer the size of Kansas for only 2 volts A/C? So, I'm guessing this might have something to do with it? I could be in left field due to my lack of knowledge and inexperience, that's why I'm hoping you guy's/girl's can shed some light. Thanks for any suggestions or hints you can provide. |
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