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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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Yaesu FRG-7700 display ???
The freqency /time display doesn't blank any of the center segments on
either time or frequency function. Any suggestions on a fix appreciated. The serial number is 59,800 and I wonder if anyone can tell me if this is an early or late model? tnx -- 73 Hank WD5JFR |
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#2
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Henry Kolesnik wrote: The freqency /time display doesn't blank any of the center segments on either time or frequency function. Any suggestions on a fix appreciated. The serial number is 59,800 and I wonder if anyone can tell me if this is an early or late model? tnx Blank or blink? -- 73 Hank WD5JFR |
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#3
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All the center segments stay bright, no blinking.
tnx -- 73 Hank WD5JFR "dxAce" wrote in message ... Henry Kolesnik wrote: The freqency /time display doesn't blank any of the center segments on either time or frequency function. Any suggestions on a fix appreciated. The serial number is 59,800 and I wonder if anyone can tell me if this is an early or late model? tnx Blank or blink? -- 73 Hank WD5JFR |
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#4
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Henry Kolesnik wrote: All the center segments stay bright, no blinking. OK, what is it you wish to blank then? I owned a FRG-7700 for several years. What exactly do you mean by 'center segments'? tnx -- 73 Hank WD5JFR "dxAce" wrote in message ... Henry Kolesnik wrote: The freqency /time display doesn't blank any of the center segments on either time or frequency function. Any suggestions on a fix appreciated. The serial number is 59,800 and I wonder if anyone can tell me if this is an early or late model? tnx Blank or blink? -- 73 Hank WD5JFR |
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#5
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It's a five digit display made of seven segment digits. The center or "G"
segment doesn't blank when zero is displayed so zero looks like an eight. It has leading zero suppression and instead of the zero being totally suppressed the center segment appears as a minus sign. -- 73 Hank WD5JFR "dxAce" wrote in message ... Henry Kolesnik wrote: All the center segments stay bright, no blinking. OK, what is it you wish to blank then? I owned a FRG-7700 for several years. What exactly do you mean by 'center segments'? tnx -- 73 Hank WD5JFR "dxAce" wrote in message ... Henry Kolesnik wrote: The freqency /time display doesn't blank any of the center segments on either time or frequency function. Any suggestions on a fix appreciated. The serial number is 59,800 and I wonder if anyone can tell me if this is an early or late model? tnx Blank or blink? -- 73 Hank WD5JFR |
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#6
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dxAce wrote:
Henry Kolesnik wrote: All the center segments stay bright, no blinking. OK, what is it you wish to blank then? I owned a FRG-7700 for several years. What exactly do you mean by 'center segments'? I think his problem is a 0 looks the same as an 8 and a 7 looks like a backwards F - the middle horizontal bar is lit all the time. tnx -- 73 Hank WD5JFR "dxAce" wrote in message ... Henry Kolesnik wrote: The freqency /time display doesn't blank any of the center segments on either time or frequency function. Any suggestions on a fix appreciated. The serial number is 59,800 and I wonder if anyone can tell me if this is an early or late model? tnx Blank or blink? -- 73 Hank WD5JFR |
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#7
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Henry Kolesnik wrote: It's a five digit display made of seven segment digits. The center or "G" segment doesn't blank when zero is displayed so zero looks like an eight. It has leading zero suppression and instead of the zero being totally suppressed the center segment appears as a minus sign. OK, I understand Hank. Sorry, I never encountered that problem. I'm certain someone will be able to help you out. -- 73 Hank WD5JFR "dxAce" wrote in message ... Henry Kolesnik wrote: All the center segments stay bright, no blinking. OK, what is it you wish to blank then? I owned a FRG-7700 for several years. What exactly do you mean by 'center segments'? tnx -- 73 Hank WD5JFR "dxAce" wrote in message ... Henry Kolesnik wrote: The freqency /time display doesn't blank any of the center segments on either time or frequency function. Any suggestions on a fix appreciated. The serial number is 59,800 and I wonder if anyone can tell me if this is an early or late model? tnx Blank or blink? -- 73 Hank WD5JFR |
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#8
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"Henry Kolesnik" wrote in message m... It's a five digit display made of seven segment digits. The center or "G" segment doesn't blank when zero is displayed so zero looks like an eight. It has leading zero suppression and instead of the zero being totally suppressed the center segment appears as a minus sign. -- 73 Hank WD5JFR It sounds like a short in the display board. Did it get dropped? Or maybe a soda spill? B.H. |
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#9
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"Henry Kolesnik" wrote in message m... All the center segments stay bright, no blinking. tnx If I understand you right, it sounds like you have a shorted transistor driving either the rows or columns of the multiplexed display. |
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#10
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Check the segment transistors position Q1052-Q1056 (2sa733a-q)
One of them will probably be shorted. The signals for the transistors are coming from ic msm5524 controlling the frequency and time display. Greetings Peter "Henry Kolesnik" schreef in bericht m... It's a five digit display made of seven segment digits. The center or "G" segment doesn't blank when zero is displayed so zero looks like an eight. It has leading zero suppression and instead of the zero being totally suppressed the center segment appears as a minus sign. -- 73 Hank WD5JFR "dxAce" wrote in message ... Henry Kolesnik wrote: All the center segments stay bright, no blinking. OK, what is it you wish to blank then? I owned a FRG-7700 for several years. What exactly do you mean by 'center segments'? tnx -- 73 Hank WD5JFR "dxAce" wrote in message ... Henry Kolesnik wrote: The freqency /time display doesn't blank any of the center segments on either time or frequency function. Any suggestions on a fix appreciated. The serial number is 59,800 and I wonder if anyone can tell me if this is an early or late model? tnx Blank or blink? -- 73 Hank WD5JFR |
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#11
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Peter
Thanks for the tip but I had previously checked the voltages on the transistors you mention and all are B +4.44, E +4.58 and C -22.4 volts. I discounted them as being the problem because there's only five and there are seven segments. My guess is that these transistors are the individual digit drivers as there are five digits and the segments are muxed from the msm5524. If I look closely at the copy of a copy many times over of the schematic I can see where a prevoius owner made notes indicating that the center segment is driven by pin 25. Any more tips appreciated. As you can tell I'm out of my league with this kind of stuff. -- 73 Hank WD5JFR "eddumweer" wrote in message ... Check the segment transistors position Q1052-Q1056 (2sa733a-q) One of them will probably be shorted. The signals for the transistors are coming from ic msm5524 controlling the frequency and time display. Greetings Peter "Henry Kolesnik" schreef in bericht m... It's a five digit display made of seven segment digits. The center or "G" segment doesn't blank when zero is displayed so zero looks like an eight. It has leading zero suppression and instead of the zero being totally suppressed the center segment appears as a minus sign. -- 73 Hank WD5JFR "dxAce" wrote in message ... Henry Kolesnik wrote: All the center segments stay bright, no blinking. OK, what is it you wish to blank then? I owned a FRG-7700 for several years. What exactly do you mean by 'center segments'? tnx -- 73 Hank WD5JFR "dxAce" wrote in message ... Henry Kolesnik wrote: The freqency /time display doesn't blank any of the center segments on either time or frequency function. Any suggestions on a fix appreciated. The serial number is 59,800 and I wonder if anyone can tell me if this is an early or late model? tnx Blank or blink? -- 73 Hank WD5JFR |
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#12
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Henry Kolesnik wrote:
Peter Thanks for the tip but I had previously checked the voltages on the transistors you mention and all are B +4.44, E +4.58 and C -22.4 volts. I discounted them as being the problem because there's only five and there are seven segments. My guess is that these transistors are the individual digit drivers as there are five digits and the segments are muxed from the msm5524. If I look closely at the copy of a copy many times over of the schematic I can see where a prevoius owner made notes indicating that the center segment is driven by pin 25. Any more tips appreciated. As you can tell I'm out of my league with this kind of stuff. This web page: http://www.crocuta.com/FRG7700/html/page20.html indicates the segments are controlled by Q1052 - Q1058 (2SA733A-Q) So there should be seven transistors there. If the transistor isn't identified in the schematic, you can narrow down the segment to one of two by tuning to all 1's and then all 2's. 2 segments will have the -25 voltage on them for both tests. You may be able to get a better handle on which of the two is bad by tuning to 15,555 - the segment that consistently reads the full -25 (or -22.5) is probably the bad one. I'm not familiar with your radio - just basic trouble shooting. -- 73 Hank WD5JFR "eddumweer" wrote in message ... Check the segment transistors position Q1052-Q1056 (2sa733a-q) One of them will probably be shorted. The signals for the transistors are coming from ic msm5524 controlling the frequency and time display. Greetings Peter "Henry Kolesnik" schreef in bericht m... It's a five digit display made of seven segment digits. The center or "G" segment doesn't blank when zero is displayed so zero looks like an eight. It has leading zero suppression and instead of the zero being totally suppressed the center segment appears as a minus sign. -- 73 Hank WD5JFR "dxAce" wrote in message ... Henry Kolesnik wrote: All the center segments stay bright, no blinking. OK, what is it you wish to blank then? I owned a FRG-7700 for several years. What exactly do you mean by 'center segments'? tnx -- 73 Hank WD5JFR "dxAce" wrote in message ... Henry Kolesnik wrote: The freqency /time display doesn't blank any of the center segments on either time or frequency function. Any suggestions on a fix appreciated. The serial number is 59,800 and I wonder if anyone can tell me if this is an early or late model? tnx Blank or blink? -- 73 Hank WD5JFR |
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#13
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I only have a bad pdf of it, so that could be the problem.
Indeed check if there are 7 of the same type of transistor there and you can try it on 2 way's. You can change them one with another or if it is a leddisplay get the suspected transistor out of it then it must go dark. If the problem is from pin 25 then check with an oscilloscoop if it's switching right, looking to another pin with the same function for another segment. Good luck PP "Henry Kolesnik" schreef in bericht m... Peter Thanks for the tip but I had previously checked the voltages on the transistors you mention and all are B +4.44, E +4.58 and C -22.4 volts. I discounted them as being the problem because there's only five and there are seven segments. My guess is that these transistors are the individual digit drivers as there are five digits and the segments are muxed from the msm5524. If I look closely at the copy of a copy many times over of the schematic I can see where a prevoius owner made notes indicating that the center segment is driven by pin 25. Any more tips appreciated. As you can tell I'm out of my league with this kind of stuff. -- 73 Hank WD5JFR "eddumweer" wrote in message ... Check the segment transistors position Q1052-Q1056 (2sa733a-q) One of them will probably be shorted. The signals for the transistors are coming from ic msm5524 controlling the frequency and time display. Greetings Peter "Henry Kolesnik" schreef in bericht m... It's a five digit display made of seven segment digits. The center or "G" segment doesn't blank when zero is displayed so zero looks like an eight. It has leading zero suppression and instead of the zero being totally suppressed the center segment appears as a minus sign. -- 73 Hank WD5JFR "dxAce" wrote in message ... Henry Kolesnik wrote: All the center segments stay bright, no blinking. OK, what is it you wish to blank then? I owned a FRG-7700 for several years. What exactly do you mean by 'center segments'? tnx -- 73 Hank WD5JFR "dxAce" wrote in message ... Henry Kolesnik wrote: The freqency /time display doesn't blank any of the center segments on either time or frequency function. Any suggestions on a fix appreciated. The serial number is 59,800 and I wonder if anyone can tell me if this is an early or late model? tnx Blank or blink? -- 73 Hank WD5JFR |
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#14
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According to my schematic Q57 and Q58 are drivers for the 2 LEDs used in the
clock mode to indicate AM or PM. Looks like I'm going to get the scope on the bench and see what happens on the various segment pins. I've not had much luck finding the data sheet on the MSM5524, anyone have any? tnx -- 73 Hank WD5JFR "eddumweer" wrote in message ... I only have a bad pdf of it, so that could be the problem. Indeed check if there are 7 of the same type of transistor there and you can try it on 2 way's. You can change them one with another or if it is a leddisplay get the suspected transistor out of it then it must go dark. If the problem is from pin 25 then check with an oscilloscoop if it's switching right, looking to another pin with the same function for another segment. Good luck PP "Henry Kolesnik" schreef in bericht m... Peter Thanks for the tip but I had previously checked the voltages on the transistors you mention and all are B +4.44, E +4.58 and C -22.4 volts. I discounted them as being the problem because there's only five and there are seven segments. My guess is that these transistors are the individual digit drivers as there are five digits and the segments are muxed from the msm5524. If I look closely at the copy of a copy many times over of the schematic I can see where a prevoius owner made notes indicating that the center segment is driven by pin 25. Any more tips appreciated. As you can tell I'm out of my league with this kind of stuff. -- 73 Hank WD5JFR "eddumweer" wrote in message ... Check the segment transistors position Q1052-Q1056 (2sa733a-q) One of them will probably be shorted. The signals for the transistors are coming from ic msm5524 controlling the frequency and time display. Greetings Peter "Henry Kolesnik" schreef in bericht m... It's a five digit display made of seven segment digits. The center or "G" segment doesn't blank when zero is displayed so zero looks like an eight. It has leading zero suppression and instead of the zero being totally suppressed the center segment appears as a minus sign. -- 73 Hank WD5JFR "dxAce" wrote in message ... Henry Kolesnik wrote: All the center segments stay bright, no blinking. OK, what is it you wish to blank then? I owned a FRG-7700 for several years. What exactly do you mean by 'center segments'? tnx -- 73 Hank WD5JFR "dxAce" wrote in message ... Henry Kolesnik wrote: The freqency /time display doesn't blank any of the center segments on either time or frequency function. Any suggestions on a fix appreciated. The serial number is 59,800 and I wonder if anyone can tell me if this is an early or late model? tnx Blank or blink? -- 73 Hank WD5JFR |
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#15
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Try here for a copy of the manual (looks complete, but I can't vouch for
it). http://www.crocuta.com/FRG7700/ Cheers. Ken "eddumweer" wrote in message ... I only have a bad pdf of it, so that could be the problem. Indeed check if there are 7 of the same type of transistor there and you can try it on 2 way's. You can change them one with another or if it is a leddisplay get the suspected transistor out of it then it must go dark. If the problem is from pin 25 then check with an oscilloscoop if it's switching right, looking to another pin with the same function for another segment. Good luck PP "Henry Kolesnik" schreef in bericht m... Peter Thanks for the tip but I had previously checked the voltages on the transistors you mention and all are B +4.44, E +4.58 and C -22.4 volts. I discounted them as being the problem because there's only five and there are seven segments. My guess is that these transistors are the individual digit drivers as there are five digits and the segments are muxed from the msm5524. If I look closely at the copy of a copy many times over of the schematic I can see where a prevoius owner made notes indicating that the center segment is driven by pin 25. Any more tips appreciated. As you can tell I'm out of my league with this kind of stuff. -- 73 Hank WD5JFR "eddumweer" wrote in message ... Check the segment transistors position Q1052-Q1056 (2sa733a-q) One of them will probably be shorted. The signals for the transistors are coming from ic msm5524 controlling the frequency and time display. Greetings Peter "Henry Kolesnik" schreef in bericht m... It's a five digit display made of seven segment digits. The center or "G" segment doesn't blank when zero is displayed so zero looks like an eight. It has leading zero suppression and instead of the zero being totally suppressed the center segment appears as a minus sign. -- 73 Hank WD5JFR "dxAce" wrote in message ... Henry Kolesnik wrote: All the center segments stay bright, no blinking. OK, what is it you wish to blank then? I owned a FRG-7700 for several years. What exactly do you mean by 'center segments'? tnx -- 73 Hank WD5JFR "dxAce" wrote in message ... Henry Kolesnik wrote: The freqency /time display doesn't blank any of the center segments on either time or frequency function. Any suggestions on a fix appreciated. The serial number is 59,800 and I wonder if anyone can tell me if this is an early or late model? tnx Blank or blink? -- 73 Hank WD5JFR |
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#16
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I fired up the scope and had nice patterns on MSM5524 pins 26 thru 31 about
20 volt PP but pin 25 had about 3volts PP . Later I pulled the chip and bent pin 25 out and plugged it back and voila, no center segment, anytime. While the chip was out I checked the pull down resistors and they're all about 100K ohms. Pin 25 which controls the center segment appears to be the problem. Now what I need to know is the the IC or could it be something else? tnx -- 73 Hank WD5JFR "Mark S. Holden" wrote in message ... Henry Kolesnik wrote: Peter Thanks for the tip but I had previously checked the voltages on the transistors you mention and all are B +4.44, E +4.58 and C -22.4 volts. I discounted them as being the problem because there's only five and there are seven segments. My guess is that these transistors are the individual digit drivers as there are five digits and the segments are muxed from the msm5524. If I look closely at the copy of a copy many times over of the schematic I can see where a prevoius owner made notes indicating that the center segment is driven by pin 25. Any more tips appreciated. As you can tell I'm out of my league with this kind of stuff. This web page: http://www.crocuta.com/FRG7700/html/page20.html indicates the segments are controlled by Q1052 - Q1058 (2SA733A-Q) So there should be seven transistors there. If the transistor isn't identified in the schematic, you can narrow down the segment to one of two by tuning to all 1's and then all 2's. 2 segments will have the -25 voltage on them for both tests. You may be able to get a better handle on which of the two is bad by tuning to 15,555 - the segment that consistently reads the full -25 (or -22.5) is probably the bad one. I'm not familiar with your radio - just basic trouble shooting. -- 73 Hank WD5JFR "eddumweer" wrote in message ... Check the segment transistors position Q1052-Q1056 (2sa733a-q) One of them will probably be shorted. The signals for the transistors are coming from ic msm5524 controlling the frequency and time display. Greetings Peter "Henry Kolesnik" schreef in bericht m... It's a five digit display made of seven segment digits. The center or "G" segment doesn't blank when zero is displayed so zero looks like an eight. It has leading zero suppression and instead of the zero being totally suppressed the center segment appears as a minus sign. -- 73 Hank WD5JFR "dxAce" wrote in message ... Henry Kolesnik wrote: All the center segments stay bright, no blinking. OK, what is it you wish to blank then? I owned a FRG-7700 for several years. What exactly do you mean by 'center segments'? tnx -- 73 Hank WD5JFR "dxAce" wrote in message ... Henry Kolesnik wrote: The freqency /time display doesn't blank any of the center segments on either time or frequency function. Any suggestions on a fix appreciated. The serial number is 59,800 and I wonder if anyone can tell me if this is an early or late model? tnx Blank or blink? -- 73 Hank WD5JFR |
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#17
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Henry Kolesnik wrote:
I fired up the scope and had nice patterns on MSM5524 pins 26 thru 31 about 20 volt PP but pin 25 had about 3volts PP . Later I pulled the chip and bent pin 25 out and plugged it back and voila, no center segment, anytime. While the chip was out I checked the pull down resistors and they're all about 100K ohms. Pin 25 which controls the center segment appears to be the problem. Now what I need to know is the the IC or could it be something else? tnx I presume this is a new acquisition for you. You've mentioned the previous owner had a note on the schematic indicating pin 25 controlled that segment. Sounds to me like he found the problem, and decided it would be easier to sell with a segment always on than always off. Murphy's law says since the MSM5524 is out of production and relatively hard to find it's the most likely problem. (besides, it's the display driver) Here's an auction for one I found as part of an unsuccessful search for a data sheet: http://search.auctions.shopping.yahoo.com/search?desc=MSM5524+&auccat=23761&st=auct&f=&apg=1 &nm=1&acc=sg&alocale=0sg&sb=desc You may be able to find a better price. |
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#18
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Ken
Thanks for the point. I have a schematic and have read some of the manual and it is misleading. I may be clueless but not as clueless as the guy who wrote them manual. I trust the schemtic because I can follow it on the PCB. The manual is all wrong on how the display works. 73 Hank WD5JFR "Ken Taylor" wrote in message ... Try here for a copy of the manual (looks complete, but I can't vouch for it). http://www.crocuta.com/FRG7700/ Cheers. Ken "eddumweer" wrote in message ... I only have a bad pdf of it, so that could be the problem. Indeed check if there are 7 of the same type of transistor there and you can try it on 2 way's. You can change them one with another or if it is a leddisplay get the suspected transistor out of it then it must go dark. If the problem is from pin 25 then check with an oscilloscoop if it's switching right, looking to another pin with the same function for another segment. Good luck PP "Henry Kolesnik" schreef in bericht m... Peter Thanks for the tip but I had previously checked the voltages on the transistors you mention and all are B +4.44, E +4.58 and C -22.4 volts. I discounted them as being the problem because there's only five and there are seven segments. My guess is that these transistors are the individual digit drivers as there are five digits and the segments are muxed from the msm5524. If I look closely at the copy of a copy many times over of the schematic I can see where a prevoius owner made notes indicating that the center segment is driven by pin 25. Any more tips appreciated. As you can tell I'm out of my league with this kind of stuff. -- 73 Hank WD5JFR "eddumweer" wrote in message ... Check the segment transistors position Q1052-Q1056 (2sa733a-q) One of them will probably be shorted. The signals for the transistors are coming from ic msm5524 controlling the frequency and time display. Greetings Peter "Henry Kolesnik" schreef in bericht m... It's a five digit display made of seven segment digits. The center or "G" segment doesn't blank when zero is displayed so zero looks like an eight. It has leading zero suppression and instead of the zero being totally suppressed the center segment appears as a minus sign. -- 73 Hank WD5JFR "dxAce" wrote in message ... Henry Kolesnik wrote: All the center segments stay bright, no blinking. OK, what is it you wish to blank then? I owned a FRG-7700 for several years. What exactly do you mean by 'center segments'? tnx -- 73 Hank WD5JFR "dxAce" wrote in message ... Henry Kolesnik wrote: The freqency /time display doesn't blank any of the center segments on either time or frequency function. Any suggestions on a fix appreciated. The serial number is 59,800 and I wonder if anyone can tell me if this is an early or late model? tnx Blank or blink? -- 73 Hank WD5JFR |
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#19
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I saw the Singapore deal but it aint worth for me. I might pay $10.00 for a
good one but no more. The 7700 isn't worth that much! If I don't have any luck I'll take it to tnext hamfest and see if I can get my money back, or find a junker. -- 73 Hank WD5JFR "Mark S. Holden" wrote in message ... Henry Kolesnik wrote: I fired up the scope and had nice patterns on MSM5524 pins 26 thru 31 about 20 volt PP but pin 25 had about 3volts PP . Later I pulled the chip and bent pin 25 out and plugged it back and voila, no center segment, anytime. While the chip was out I checked the pull down resistors and they're all about 100K ohms. Pin 25 which controls the center segment appears to be the problem. Now what I need to know is the the IC or could it be something else? tnx I presume this is a new acquisition for you. You've mentioned the previous owner had a note on the schematic indicating pin 25 controlled that segment. Sounds to me like he found the problem, and decided it would be easier to sell with a segment always on than always off. Murphy's law says since the MSM5524 is out of production and relatively hard to find it's the most likely problem. (besides, it's the display driver) Here's an auction for one I found as part of an unsuccessful search for a data sheet: http://search.auctions.shopping.yahoo.com/search?desc=MSM5524+&auccat=23761&st=auct&f=&apg=1 &nm=1&acc=sg&alocale=0sg&sb=desc You may be able to find a better price. |
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#20
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No problems, just thought a clearer version may assist. I don't recall if
Yaesu had a propensity for using IC sockets (I fear not) but you should be able to pull the segment drive pins down to the reference voltage (pin 1 of the IC) using, say, a 10k resistor without causing damage. (Is the display connected via one of those fairly rigid ribbon cable connectors??). Thus you can light the segments up one by one (for all digits, obviously) to check operation. OKI made these beasts but don't even list them in the obsolete components http://www2.okisemi.com/us/docs/PrdD...oducts.txt1525 but an e-mail may be rewarded. www.1sourcecomponents.com claim to have these IC's in stock, but who knows how much. I think I'm actually looking at one right now on a VFD board from an ancient satellite dish controller (I'll confirm the part number if it becomes an issue), but as I'm here in New Zealand it may be of limited use if you can find one more local to yourself. Let me know though, I can send it over. Cheers. Ken "Henry Kolesnik" wrote in message om... Ken Thanks for the point. I have a schematic and have read some of the manual and it is misleading. I may be clueless but not as clueless as the guy who wrote them manual. I trust the schemtic because I can follow it on the PCB. The manual is all wrong on how the display works. 73 Hank WD5JFR "Ken Taylor" wrote in message ... Try here for a copy of the manual (looks complete, but I can't vouch for it). http://www.crocuta.com/FRG7700/ Cheers. Ken "eddumweer" wrote in message ... I only have a bad pdf of it, so that could be the problem. Indeed check if there are 7 of the same type of transistor there and you can try it on 2 way's. You can change them one with another or if it is a leddisplay get the suspected transistor out of it then it must go dark. If the problem is from pin 25 then check with an oscilloscoop if it's switching right, looking to another pin with the same function for another segment. Good luck PP "Henry Kolesnik" schreef in bericht m... Peter Thanks for the tip but I had previously checked the voltages on the transistors you mention and all are B +4.44, E +4.58 and C -22.4 volts. I discounted them as being the problem because there's only five and there are seven segments. My guess is that these transistors are the individual digit drivers as there are five digits and the segments are muxed from the msm5524. If I look closely at the copy of a copy many times over of the schematic I can see where a prevoius owner made notes indicating that the center segment is driven by pin 25. Any more tips appreciated. As you can tell I'm out of my league with this kind of stuff. -- 73 Hank WD5JFR "eddumweer" wrote in message ... Check the segment transistors position Q1052-Q1056 (2sa733a-q) One of them will probably be shorted. The signals for the transistors are coming from ic msm5524 controlling the frequency and time display. Greetings Peter "Henry Kolesnik" schreef in bericht m... It's a five digit display made of seven segment digits. The center or "G" segment doesn't blank when zero is displayed so zero looks like an eight. It has leading zero suppression and instead of the zero being totally suppressed the center segment appears as a minus sign. -- 73 Hank WD5JFR "dxAce" wrote in message ... Henry Kolesnik wrote: All the center segments stay bright, no blinking. OK, what is it you wish to blank then? I owned a FRG-7700 for several years. What exactly do you mean by 'center segments'? tnx -- 73 Hank WD5JFR "dxAce" wrote in message ... Henry Kolesnik wrote: The freqency /time display doesn't blank any of the center segments on either time or frequency function. Any suggestions on a fix appreciated. The serial number is 59,800 and I wonder if anyone can tell me if this is an early or late model? tnx Blank or blink? -- 73 Hank WD5JFR |
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#21
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In article ,
Henry Kolesnik wrote: According to my schematic Q57 and Q58 are drivers for the 2 LEDs used in the clock mode to indicate AM or PM. Looks like I'm going to get the scope on the bench and see what happens on the various segment pins. I've not had much luck finding the data sheet on the MSM5524, anyone have any? The service manual for the (Trio)Kenwood R-1000 has a lot on it. Internal block diagram and pinout. I got the pdf from the mods.dk site. Mark Zenier Washington State resident |
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Thanks Mark I'll go to .dk and get whatever they have.
-- 73 Hank WD5JFR "Mark Zenier" wrote in message ... In article , Henry Kolesnik wrote: According to my schematic Q57 and Q58 are drivers for the 2 LEDs used in the clock mode to indicate AM or PM. Looks like I'm going to get the scope on the bench and see what happens on the various segment pins. I've not had much luck finding the data sheet on the MSM5524, anyone have any? The service manual for the (Trio)Kenwood R-1000 has a lot on it. Internal block diagram and pinout. I got the pdf from the mods.dk site. Mark Zenier Washington State resident |
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Linear Mode
