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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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Pioneer SDP5073 capacitor gets warm
So I've been working on this nice 50" RPTV on and off now for about 2 years,
*finally* made a bunch of progress. Power supply had blown up, fixed that. Audio amp chip was shorted causing shutdown, HV was excessive causing shutdown, finally found a shorted transistor and now the HV seems to be ok. Now there's a 10uF 250v electrolytic over near the flyback that gets quite warm, this is a replacement since the original was bulged. One side connects to ground, the other connects to the flyback and a diode nearby. Diode checks good, I thought maybe it originally blew because of the excessive HV but it still gets a bit warm, any suggestions? This has been quite a project, I don't think I've ever replaced so many components in a single unit. |
#2
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Pioneer SDP5073 capacitor gets warm
Which transistor was shorted? I had one last year that had an intermittent
arc in the Red CRT that was causing it to eat transistors and shut down. It was a bear to track down until I got lucky and saw it arc. I'd hang a probe on the diode and see if it is leaky or slow. You might have some spikes causing the cap to get warm. Of course, you might have installed the cap backwards (I still do that occasionally), but you would probably know that by now. Leonard "James Sweet" wrote in message ... So I've been working on this nice 50" RPTV on and off now for about 2 years, *finally* made a bunch of progress. Power supply had blown up, fixed that. Audio amp chip was shorted causing shutdown, HV was excessive causing shutdown, finally found a shorted transistor and now the HV seems to be ok. Now there's a 10uF 250v electrolytic over near the flyback that gets quite warm, this is a replacement since the original was bulged. One side connects to ground, the other connects to the flyback and a diode nearby. Diode checks good, I thought maybe it originally blew because of the excessive HV but it still gets a bit warm, any suggestions? This has been quite a project, I don't think I've ever replaced so many components in a single unit. |
#3
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Pioneer SDP5073 capacitor gets warm
"Leonard Caillouet" wrote in message news:z1NOc.5475$FW1.3769@lakeread06... Which transistor was shorted? I had one last year that had an intermittent arc in the Red CRT that was causing it to eat transistors and shut down. It was a bear to track down until I got lucky and saw it arc. I'd hang a probe on the diode and see if it is leaky or slow. You might have some spikes causing the cap to get warm. Of course, you might have installed the cap backwards (I still do that occasionally), but you would probably know that by now. Leonard I don't recall the board location and it's not convenient to yank it out at the moment to look, but the transistor that was shorted is a TO-220 case darlington transistor mounted on the big heatsink near the front of the board (front meaning towards the screen when installed.) Took me forever to track that one down, checked it several times and figured the apparent short was the internal resistor that the nearby HOT has. I haven't run it long enough to find out just how warm the capacitor gets, figured it it was getting warm at all something was wrong but perhaps not. My replacement is physically much smaller than the original, I'm hoping there wasn't anything special about the one that was there. |
#4
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Pioneer SDP5073 capacitor gets warm
"James Sweet" wrote in message news "Leonard Caillouet" wrote in message news:z1NOc.5475$FW1.3769@lakeread06... Which transistor was shorted? I had one last year that had an intermittent arc in the Red CRT that was causing it to eat transistors and shut down. It was a bear to track down until I got lucky and saw it arc. I'd hang a probe on the diode and see if it is leaky or slow. You might have some spikes causing the cap to get warm. Of course, you might have installed the cap backwards (I still do that occasionally), but you would probably know that by now. Leonard I don't recall the board location and it's not convenient to yank it out at the moment to look, but the transistor that was shorted is a TO-220 case darlington transistor mounted on the big heatsink near the front of the board (front meaning towards the screen when installed.) Took me forever to track that one down, checked it several times and figured the apparent short was the internal resistor that the nearby HOT has. I haven't run it long enough to find out just how warm the capacitor gets, figured it it was getting warm at all something was wrong but perhaps not. My replacement is physically much smaller than the original, I'm hoping there wasn't anything special about the one that was there. That is the one that I had bad, but it also had a bad HOT. When I replaced both and fired it up it would eat the smaller one almost immediately. Hope you don't have this scenario. I doubt it because these CRT shorts are catastrophic, your hot cap is likely due to something else, unless the cap itself was leaky. Don't you just love how they designed these to be so easy to access to troubleshoot? Don't forget to resolder virtually every joint on the board, BTW. Leonard |
#5
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Pioneer SDP5073 capacitor gets warm
I haven't run it long enough to find out just how warm the capacitor gets, figured it it was getting warm at all something was wrong but perhaps not. My replacement is physically much smaller than the original, I'm hoping there wasn't anything special about the one that was there. That is the one that I had bad, but it also had a bad HOT. When I replaced both and fired it up it would eat the smaller one almost immediately. Hope you don't have this scenario. I doubt it because these CRT shorts are catastrophic, your hot cap is likely due to something else, unless the cap itself was leaky. Don't you just love how they designed these to be so easy to access to troubleshoot? Don't forget to resolder virtually every joint on the board, BTW. Leonard Well I ran it for about 20 minutes and the capacitor gets quite warm to the touch but not incredibly hot, the original diode was a bit leaky so I replaced it quite some time ago with a horizontal damper diode from a PC monitor, figured that should be fast enough, anyway one more problem I can't figure out, the remote doesn't work, I know it's not the remote because it works on another similar set. |
#6
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Pioneer SDP5073 capacitor gets warm
James,
Doesn't that model use a keyboard/IR detector processor IC? I know the SD-P5062 does but the 5191 doesn't. Worth a look. Good Luck, Bill Jr "James Sweet" wrote in message ... I haven't run it long enough to find out just how warm the capacitor gets, figured it it was getting warm at all something was wrong but perhaps not. My replacement is physically much smaller than the original, I'm hoping there wasn't anything special about the one that was there. That is the one that I had bad, but it also had a bad HOT. When I replaced both and fired it up it would eat the smaller one almost immediately. Hope you don't have this scenario. I doubt it because these CRT shorts are catastrophic, your hot cap is likely due to something else, unless the cap itself was leaky. Don't you just love how they designed these to be so easy to access to troubleshoot? Don't forget to resolder virtually every joint on the board, BTW. Leonard Well I ran it for about 20 minutes and the capacitor gets quite warm to the touch but not incredibly hot, the original diode was a bit leaky so I replaced it quite some time ago with a horizontal damper diode from a PC monitor, figured that should be fast enough, anyway one more problem I can't figure out, the remote doesn't work, I know it's not the remote because it works on another similar set. |
#7
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Pioneer SDP5073 capacitor gets warm
"Bill Jr" wrote in message .. . James, Doesn't that model use a keyboard/IR detector processor IC? I know the SD-P5062 does but the 5191 doesn't. Worth a look. Good Luck, Bill Jr I sure don't see one, there's only a few IC's on the whole board aside from the micro and I've been able to find datasheets for pretty much all of them. I'm looking at the ANP1685 board, I believe the three large vertically standing boards in the stack are all AV processing stuff. |
#8
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Pioneer SDP5073 capacitor gets warm
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