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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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Tektronix 466 Scope Problem
Hi guys. I'm hoping that some of the more Electronics oriented
individuals out there may be able to help me. I am pretty much self taught when it comes to electronics so my knowledge is very limited. I always try my very best to troubleshoot and fix things when I have a problem and believe it or not, I'm successful about 90% of the time. Mainly it's because I can see the "burned" part or "hair line" fracture in the solder board. Well my Tektronix scope was something I purchased from e-bay about 2 years ago. It worked perfectly from what I could tell. I was very new to scopes and didn't have any experience running them. My friend came over one day and was like "oh yeah I can show you how to run a scope... bla bla." To make a long story short during a calibration discussion he suggested we simply test the AC "house current" for the 60 cycles per second that it should be. I don't remember exactly how we connected the probes to the AC but when I made the final connection the circuit breaker popped and I looked at him with a rather "****ed off" expression. I was sure my scope was ruined. I reset the breaker and turned the scope on. It worked fine ..."See it's ok" my friend said! About 10 or 15 seconds later my scope went into a rather "dead" state. -Needless to say I was ****ed. I take pride in all of my equipment ...no matter how old it is. I take good care of it and try to learn as much as I can with what I have. We checked the fuses and they were both fine in the scope. He then said ..."I'll take it to work dude. My buddy Hank at work fixes these things all day long. He'll have it up and running in under 10 minutes I bet." Needless to say about 4 months later I got it back ...still broken. All Hank told my friend was something about the DC power supply? I assume that means that one of the full wave bridge rectifiers is bad? -But if that's the case why didn't he find which one and replace it? Anyway, from what I can tell, by turning the scope on for several seconds here is what DOES come on: The lights on the front light up. The trace dots do come up after a few seconds on the screen, but they do not move. They get so bright (maybe because they are not moving?) that I turn the scope off quickly in fear of it burning something further out. The fan on the back DOES NOT run anymore and the time portion does not appear to work since I see only 1 bright or 2 bright dots in the center (I think it's 2 of them). I am willing to try or test anything you can suggest to help me fix this. Please help if you can Thank You, -Chris |
#2
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Tektronix 466 Scope Problem
"Chris" chris1@oupower_dot_com wrote in message m... Hi guys. I'm hoping that some of the more Electronics oriented individuals out there may be able to help me. I am pretty much self taught when it comes to electronics so my knowledge is very limited. I always try my very best to troubleshoot and fix things when I have a problem and believe it or not, I'm successful about 90% of the time. Mainly it's because I can see the "burned" part or "hair line" fracture in the solder board. Well my Tektronix scope was something I purchased from e-bay about 2 years ago. It worked perfectly from what I could tell. I was very new to scopes and didn't have any experience running them. My friend came over one day and was like "oh yeah I can show you how to run a scope... bla bla." To make a long story short during a calibration discussion he suggested we simply test the AC "house current" for the 60 cycles per second that it should be. I don't remember exactly how we connected the probes to the AC but when I made the final connection the circuit breaker popped and I looked at him with a rather "****ed off" expression. I was sure my scope was ruined. I reset the breaker and turned the scope on. It worked fine ..."See it's ok" my friend said! About 10 or 15 seconds later my scope went into a rather "dead" state. -Needless to say I was ****ed. I take pride in all of my equipment ...no matter how old it is. I take good care of it and try to learn as much as I can with what I have. We checked the fuses and they were both fine in the scope. He then said ..."I'll take it to work dude. My buddy Hank at work fixes these things all day long. He'll have it up and running in under 10 minutes I bet." Needless to say about 4 months later I got it back ...still broken. All Hank told my friend was something about the DC power supply? I assume that means that one of the full wave bridge rectifiers is bad? -But if that's the case why didn't he find which one and replace it? Anyway, from what I can tell, by turning the scope on for several seconds here is what DOES come on: The lights on the front light up. The trace dots do come up after a few seconds on the screen, but they do not move. They get so bright (maybe because they are not moving?) that I turn the scope off quickly in fear of it burning something further out. The fan on the back DOES NOT run anymore and the time portion does not appear to work since I see only 1 bright or 2 bright dots in the center (I think it's 2 of them). I am willing to try or test anything you can suggest to help me fix this. Please help if you can Thank You, -Chris Sounds like one output of the power supply is dead, you'll need to do some testing, do you have a multimeter? Turn the brightness way down, the static dot will burn into the tube quickly. |
#3
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Tektronix 466 Scope Problem
On Mon, 10 Nov 2003 02:30:08 GMT, "James Sweet"
wrote: "Chris" chris1@oupower_dot_com wrote in message om... Hi guys. I'm hoping that some of the more Electronics oriented individuals out there may be able to help me. I am pretty much self taught when it comes to electronics so my knowledge is very limited. I always try my very best to troubleshoot and fix things when I have a problem and believe it or not, I'm successful about 90% of the time. Mainly it's because I can see the "burned" part or "hair line" fracture in the solder board. Well my Tektronix scope was something I purchased from e-bay about 2 years ago. It worked perfectly from what I could tell. I was very new to scopes and didn't have any experience running them. My friend came over one day and was like "oh yeah I can show you how to run a scope... bla bla." To make a long story short during a calibration discussion he suggested we simply test the AC "house current" for the 60 cycles per second that it should be. I don't remember exactly how we connected the probes to the AC but when I made the final connection the circuit breaker popped and I looked at him with a rather "****ed off" expression. I was sure my scope was ruined. I reset the breaker and turned the scope on. It worked fine ..."See it's ok" my friend said! About 10 or 15 seconds later my scope went into a rather "dead" state. -Needless to say I was ****ed. I take pride in all of my equipment ...no matter how old it is. I take good care of it and try to learn as much as I can with what I have. We checked the fuses and they were both fine in the scope. He then said ..."I'll take it to work dude. My buddy Hank at work fixes these things all day long. He'll have it up and running in under 10 minutes I bet." Needless to say about 4 months later I got it back ...still broken. All Hank told my friend was something about the DC power supply? I assume that means that one of the full wave bridge rectifiers is bad? -But if that's the case why didn't he find which one and replace it? Anyway, from what I can tell, by turning the scope on for several seconds here is what DOES come on: The lights on the front light up. The trace dots do come up after a few seconds on the screen, but they do not move. They get so bright (maybe because they are not moving?) that I turn the scope off quickly in fear of it burning something further out. The fan on the back DOES NOT run anymore and the time portion does not appear to work since I see only 1 bright or 2 bright dots in the center (I think it's 2 of them). I am willing to try or test anything you can suggest to help me fix this. Please help if you can Thank You, -Chris Sounds like one output of the power supply is dead, you'll need to do some testing, do you have a multimeter? Turn the brightness way down, the static dot will burn into the tube quickly. James, I have started to test the transformer and it appears to be good. I have 5 labeled pins on the transformer (10 - 14) and they all measure resistance so I assume the windings are all intact. I started measuring with my multi-meter by connecting my negative probe to the ground and then testing various points with the positive probe, while the power was on to my scope. Everything appears normal from the few things I have tested, except for the 1 full wave bridge rectifier. It is getting some strange readings. Maybe this is the problem or maybe the capacitor that it's connected to is the problem? I would love to check some values against anyone with another 466 scope. Can I ask for some assistance in that area please guys? If you have a TEK 466 storage scope, please let me know and I'll tell you which rectifier measured oddly and how I got the measurement. Are there any repair manuals with these that I can download or order? I would like to know if there is some simple standard tests to try to pinpoint my problem. I am very new to troubleshooting electronics like this but I'm willing to learn The DOT is off to the side far enough that it is not visible. I have tried to center it to see the dot but can not, I played with the "Find Beam" and that does center it, but I only dare to hit the button for a moment, as I don't want to burn my screen. I have turned it down as far as I can so I just don't keep the scope turned on very long while I'm testing. I hope I am not hurting it during my short tests. I'm looking for any help you guys can offer. I can not afford to send it in for repairs so I have to do this with your help if you can help I am grateful! -Chris |
#4
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Tektronix 466 Scope Problem
Jack, do you have a repair manual for the 466 scopes that I can
obtain? If not, perhaps you have some testing procedures or instructions I can get? Thank You, -Chris On Tue, 9 Dec 2003 21:49:39 -0600, "Jack" wrote: http://www.tyrosys.com/cal.html "Chris" chris1@oupower_dot_com wrote in message om... Hi guys. I'm hoping that some of the more Electronics oriented individuals out there may be able to help me. I am pretty much self taught when it comes to electronics so my knowledge is very limited. I always try my very best to troubleshoot and fix things when I have a problem and believe it or not, I'm successful about 90% of the time. Mainly it's because I can see the "burned" part or "hair line" fracture in the solder board. Well my Tektronix scope was something I purchased from e-bay about 2 years ago. It worked perfectly from what I could tell. I was very new to scopes and didn't have any experience running them. My friend came over one day and was like "oh yeah I can show you how to run a scope... bla bla." To make a long story short during a calibration discussion he suggested we simply test the AC "house current" for the 60 cycles per second that it should be. I don't remember exactly how we connected the probes to the AC but when I made the final connection the circuit breaker popped and I looked at him with a rather "****ed off" expression. I was sure my scope was ruined. I reset the breaker and turned the scope on. It worked fine ..."See it's ok" my friend said! About 10 or 15 seconds later my scope went into a rather "dead" state. -Needless to say I was ****ed. I take pride in all of my equipment ...no matter how old it is. I take good care of it and try to learn as much as I can with what I have. We checked the fuses and they were both fine in the scope. He then said ..."I'll take it to work dude. My buddy Hank at work fixes these things all day long. He'll have it up and running in under 10 minutes I bet." Needless to say about 4 months later I got it back ...still broken. All Hank told my friend was something about the DC power supply? I assume that means that one of the full wave bridge rectifiers is bad? -But if that's the case why didn't he find which one and replace it? Anyway, from what I can tell, by turning the scope on for several seconds here is what DOES come on: The lights on the front light up. The trace dots do come up after a few seconds on the screen, but they do not move. They get so bright (maybe because they are not moving?) that I turn the scope off quickly in fear of it burning something further out. The fan on the back DOES NOT run anymore and the time portion does not appear to work since I see only 1 bright or 2 bright dots in the center (I think it's 2 of them). I am willing to try or test anything you can suggest to help me fix this. Please help if you can Thank You, -Chris |
#5
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Tektronix 466 Scope Problem
My first suggestion is to get a 466 SERVICE manual,with the parts lists,schematics,and VERY important;the CIRCUIT DESCRIPTIONS,which are very detailed,and tell how each section of your scope work. Try Ebay or www.big-list.com,TEK no longer supports this model. In connecting to the AC mains,it's very likely that you burned up some ground runs on circuit boards. IIRC,TEK has some literature on why one should not make un-isolated measurements with grounded scopes. www.tek.com. -- Jim Yanik,NRA member jyanik-at-kua.net |
#6
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Tektronix 466 Scope Problem
Does anyone have an online version of the TEK 466 Service manual with
the Circuit Descriptions that Jim recommends? I would bet these things are available in Adobe format. I would be grateful to anyone who has an online manual, if they would be kind enough to e-mail it to me. Thank You, -Chris On Mon, 10 Nov 2003 16:21:00 +0000 (UTC), Jim Yanik wrote: My first suggestion is to get a 466 SERVICE manual,with the parts lists,schematics,and VERY important;the CIRCUIT DESCRIPTIONS,which are very detailed,and tell how each section of your scope work. Try Ebay or www.big-list.com,TEK no longer supports this model. In connecting to the AC mains,it's very likely that you burned up some ground runs on circuit boards. IIRC,TEK has some literature on why one should not make un-isolated measurements with grounded scopes. www.tek.com. -- Jim Yanik,NRA member jyanik-at-kua.net |
#7
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Tektronix 466 Scope Problem
"Chris" chris1@oupower_dot_com wrote in message om... Does anyone have an online version of the TEK 466 Service manual with the Circuit Descriptions that Jim recommends? I would bet these things are available in Adobe format. I would be grateful to anyone who has an online manual, if they would be kind enough to e-mail it to me. These scopes became "obsolete" long before Adobe Acrobat appeared, and before there was a practical way of moving computer files around if it had existed. They're still great scopes, but you won't find the documentation online, you'll have to buy the real manual or find someone who can photocopy the relevant section for you. |
#8
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Tektronix 466 Scope Problem
chris1@oupower_dot_com (Chris) wrote in message om...
...SNIPPED.. Thank You, -Chris Hi Cris, as Jim pointed to: You need a schematic. for a guideline: Looks like the +15V pwr supply has dies during your "house AC test". Go to logsa.army.mil, do a search for tektronix and download the 475 scope manual (jep, 475, not 466 - since there is no 466 in logsa). The pwr supply in the LV section is pretty much the same to the 466. And then download from from http://www.teknetelectronics.com the Tektronix 466 operating manual -- this will help your friend teach how to use the scope. Both sites are free download, just follow the instructions (or google in the web). good luck for the repair. scnr, Andreas |
#9
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Tektronix 466 Scope Problem
------------------------------------
[Flamers, note: This reply is "top-posted" so people using the Google Groups website don't have to click on "See the rest of this message". (Get over it.)] Chris, The power supply's test points' voltages (relative to chassis ground) should be labeled, right on the circuit board. If those voltages aren't all within a few percent of nominal, fix them before looking for anything else. You can also check the AC ripple on them. Most of them should probably have less than about 20 mv of AC. For Tektronix service manuals, there are many places to buy. At http://www.w7fg.com, they have truly-excellent-quality photocopies, with proper foldout schematics, nicely bound, etc., that are usually significantly cheaper than original manuals. I am not aware of *any* PDF version of the 466 service manual, although the sites mentioned by others do have the 466 *ops* manual. I have more sources for Tek manuals and info, listed at: http://www.fullnet.com/u/tomg/links.htm I will also email you my list of the "best" sources for Tek manuals and parts. If you had another scope to use to troubleshoot your 466, it might be very helpful. The service manual has sample waveforms, etc, for you to check, in many places in your scope. You could also use another scope to build (in minutes) a "quick and dirty curve tracer", to test components (in-circuit, if you use a low-enough voltage; power OFF of course), such as the one described at: http://www.repairfaq.org/REPAIR/F_semitest.html#stqdc You could also use a second scope to test the ESR (Equivalent Series Resistance) of the electrolytic capacitors, which is a very good way to check for their common failure mode, using the technique outlined at: http://www.fullnet.com/u/tomg/esrscope.htm Another alternative: You should be able to find a 466 that's "almost working" at http://www.ebay.com, probably for less than $100. Then you could compare measurments between that 466 and your 466. Maybe you could even fix that one instead. Either way, having two of them side-by-side can be a great aid in tracking down a problem. Good luck! Regards, Tom Gootee ------------------------------------ chris1@oupower_dot_com (Chris) wrote in message om... Hi guys. I'm hoping that some of the more Electronics oriented individuals out there may be able to help me. I am pretty much self taught when it comes to electronics so my knowledge is very limited. I always try my very best to troubleshoot and fix things when I have a problem and believe it or not, I'm successful about 90% of the time. Mainly it's because I can see the "burned" part or "hair line" fracture in the solder board. Well my Tektronix scope was something I purchased from e-bay about 2 years ago. It worked perfectly from what I could tell. I was very new to scopes and didn't have any experience running them. My friend came over one day and was like "oh yeah I can show you how to run a scope... bla bla." To make a long story short during a calibration discussion he suggested we simply test the AC "house current" for the 60 cycles per second that it should be. I don't remember exactly how we connected the probes to the AC but when I made the final connection the circuit breaker popped and I looked at him with a rather "****ed off" expression. I was sure my scope was ruined. I reset the breaker and turned the scope on. It worked fine ..."See it's ok" my friend said! About 10 or 15 seconds later my scope went into a rather "dead" state. -Needless to say I was ****ed. I take pride in all of my equipment ...no matter how old it is. I take good care of it and try to learn as much as I can with what I have. We checked the fuses and they were both fine in the scope. He then said ..."I'll take it to work dude. My buddy Hank at work fixes these things all day long. He'll have it up and running in under 10 minutes I bet." Needless to say about 4 months later I got it back ...still broken. All Hank told my friend was something about the DC power supply? I assume that means that one of the full wave bridge rectifiers is bad? -But if that's the case why didn't he find which one and replace it? Anyway, from what I can tell, by turning the scope on for several seconds here is what DOES come on: The lights on the front light up. The trace dots do come up after a few seconds on the screen, but they do not move. They get so bright (maybe because they are not moving?) that I turn the scope off quickly in fear of it burning something further out. The fan on the back DOES NOT run anymore and the time portion does not appear to work since I see only 1 bright or 2 bright dots in the center (I think it's 2 of them). I am willing to try or test anything you can suggest to help me fix this. Please help if you can Thank You, -Chris |
#10
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Tektronix 466 Scope Problem
"James Sweet" wrote in message news:PXTrb.120249$9E1.592552@attbi_s52... "Chris" chris1@oupower_dot_com wrote in message om... Does anyone have an online version of the TEK 466 Service manual with the Circuit Descriptions that Jim recommends? I would bet these things are available in Adobe format. I would be grateful to anyone who has an online manual, if they would be kind enough to e-mail it to me. These scopes became "obsolete" long before Adobe Acrobat appeared, and before there was a practical way of moving computer files around if it had existed. They're still great scopes, but you won't find the documentation online, you'll have to buy the real manual or find someone who can photocopy the relevant section for you. Try http://www.fullnet.com/u/tomg/manuals.htm |
#11
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Tektronix 466 Scope Problem
On 12 Nov 2003 04:51:16 -0800, TekMan wrote:
Go to logsa.army.mil, do a search for tektronix and download the 475 scope manual (jep, 475, not 466 - since there is no 466 in logsa). logsa.army.mil doesn't seem to be a valid hostname. -- | David Gersic | | Anagram: Dormitory = Dirty Room | | Email address is munged to avoid spammers. Remove the underscores. | |
#12
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Tektronix 466 Scope Problem
http://www.logsa.army.mil/etms/find_etm.cfm
"David Gersic" wrote in message ... On 12 Nov 2003 04:51:16 -0800, TekMan wrote: Go to logsa.army.mil, do a search for tektronix and download the 475 scope manual (jep, 475, not 466 - since there is no 466 in logsa). logsa.army.mil doesn't seem to be a valid hostname. Try http://www.logsa.army.mil/etms/find_etm.cfm Scott -- | David Gersic | | Anagram: Dormitory = Dirty Room | | Email address is munged to avoid spammers. Remove the underscores. | |
#13
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Tektronix 466 Scope Problem
http://www.tyrosys.com/cal.html
"Chris" chris1@oupower_dot_com wrote in message m... Hi guys. I'm hoping that some of the more Electronics oriented individuals out there may be able to help me. I am pretty much self taught when it comes to electronics so my knowledge is very limited. I always try my very best to troubleshoot and fix things when I have a problem and believe it or not, I'm successful about 90% of the time. Mainly it's because I can see the "burned" part or "hair line" fracture in the solder board. Well my Tektronix scope was something I purchased from e-bay about 2 years ago. It worked perfectly from what I could tell. I was very new to scopes and didn't have any experience running them. My friend came over one day and was like "oh yeah I can show you how to run a scope... bla bla." To make a long story short during a calibration discussion he suggested we simply test the AC "house current" for the 60 cycles per second that it should be. I don't remember exactly how we connected the probes to the AC but when I made the final connection the circuit breaker popped and I looked at him with a rather "****ed off" expression. I was sure my scope was ruined. I reset the breaker and turned the scope on. It worked fine ..."See it's ok" my friend said! About 10 or 15 seconds later my scope went into a rather "dead" state. -Needless to say I was ****ed. I take pride in all of my equipment ...no matter how old it is. I take good care of it and try to learn as much as I can with what I have. We checked the fuses and they were both fine in the scope. He then said ..."I'll take it to work dude. My buddy Hank at work fixes these things all day long. He'll have it up and running in under 10 minutes I bet." Needless to say about 4 months later I got it back ...still broken. All Hank told my friend was something about the DC power supply? I assume that means that one of the full wave bridge rectifiers is bad? -But if that's the case why didn't he find which one and replace it? Anyway, from what I can tell, by turning the scope on for several seconds here is what DOES come on: The lights on the front light up. The trace dots do come up after a few seconds on the screen, but they do not move. They get so bright (maybe because they are not moving?) that I turn the scope off quickly in fear of it burning something further out. The fan on the back DOES NOT run anymore and the time portion does not appear to work since I see only 1 bright or 2 bright dots in the center (I think it's 2 of them). I am willing to try or test anything you can suggest to help me fix this. Please help if you can Thank You, -Chris |
#14
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Tektronix 466 Scope Problem
The first thing you have to do is get a schematic. Once you find the schematic
and are able to find the FAN you MAY find the entire problem. It is probably a power supply problem. But, you need to know what supplies are generated and where. Once you know that you are in business. Also, check very carefully for any more fuses. Sometimes they are very cleverly hidden.ince the fan does not run it may be just a matter of finding the powerr supply that suplies the fan. There may even be a sticker on the fan which will tell you what voltage it is. Then search out that power supply. Roy |
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