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winny
Joined: 09 Oct 2013
Posts: 403
Location: Sweden
TV/Projector: BD808s, BG1209/2
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| Posted: Thu Jul 16, 2015 7:13 pm Post subject: |
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Didn't hear from Curt so I went ahead with the Rohm transistor. Didn't pop but no high voltage and I smelled burning. Turned off and the transistor was very hot.
Shorted tube? Failed splitter? Failed quad?
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| Melifluonze wrote: | | Digital is easy. This is torture, but far more interesting... |
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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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| Posted: Thu Jul 16, 2015 7:42 pm Post subject: |
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Sorry, I missed following up. I've been doing a lot of service on BArco HV sections lately, and the transistor running hot can be a bad drive circuit on the EHT board.. which is terribly complex to repair, despite the 'simple' circuit on the board, or a shorted quadrupler, overloading the transistor.. or both. I've had a few shorted quads then short out the EHT transistor, which damages the board, and replacement transistors run very hot and short out again within minutes. No way to tell which one (or both) it is, unless you want to send them to me for testing. The HV splitter should be OK most likely.
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winny
Joined: 09 Oct 2013
Posts: 403
Location: Sweden
TV/Projector: BD808s, BG1209/2
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| Posted: Fri Jul 17, 2015 12:50 pm Post subject: |
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I see. Well, designing SMPS's is my job so no problem in diagnosing the drive section.
As for the quad, the white return wire, is there a trick to get it out or just cheat and solder it from the top side or cut and splice?
Can I run it with the tubes disconnected to rule them out?
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| Melifluonze wrote: | | Digital is easy. This is torture, but far more interesting... |
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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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| Posted: Fri Jul 17, 2015 1:43 pm Post subject: |
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Sorry, I don't give out component troubleshooting information. That's my core business here, and keeps this site alive.
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winny
Joined: 09 Oct 2013
Posts: 403
Location: Sweden
TV/Projector: BD808s, BG1209/2
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| Posted: Fri Jul 17, 2015 2:21 pm Post subject: |
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No need, I respect that and didn't ask for it.
How about running with the tubes disconnected and getting the quad out?
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| Melifluonze wrote: | | Digital is easy. This is torture, but far more interesting... |
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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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| Posted: Fri Jul 17, 2015 2:26 pm Post subject: |
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The main yokes need to stay connected, the set will turn on fine with the tube HV leads connected and the CRT socket/focus yoke disconnected.
Unsolder the white wire, don't cut it.
The screws for the quad are under the side cover, 4 Philips screws remove that side panel/.
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