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Old 04-15-2019, 05:06 PM   #1
ricosavy
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Default tc-p50gt30

My is sc board is shorting out replaced the 30f131 and rf1501 .Soon as i turn the tv on it shorts out.So what i did was put a light bulb in power cord when i turn tv on it lights on for a sec or two and tv shouts off.I disconnect the sc board from power supply and bulb lights up.Also disconnect the ss board and bulb still lights up.When i disconnect Ps2 on power supply the bulb does not light up and gets a 8blink code.I was wondering if my power supply is shorted.Looks like that supplies power to sc board.
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Old 04-15-2019, 08:14 PM   #2
ricosavy
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Default Re: tc-p50gt30

the bulb i am using is 100w is that ok .
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Old 04-16-2019, 12:12 PM   #3
Unspun01
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Default Re: tc-p50gt30

Upload photos of YOUR SC board with YOUR repairs.

Which 30F131 IGBTs did you replace?

There are usually 6 that burn out together Q401, Q402, Q403 and Q421, Q422, Q423. The diodes do not usually need to be replaced but may come in some kits. I have never had a diode fail in any of the TNPA5335 SC boards I've fixed.

I don't recall seeing the three 30F131 at positions Q621, Q622, Q623 fail so I usually leave them alone if they test ok.

Please reply with answers to my questions. I'm concerned you did not replace the correct IGBTs, or there may be more shorts that are still on the board.
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Old 04-17-2019, 10:34 AM   #4
ricosavy
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Default Re: tc-p50gt30

I replaced the ones you mentioned and the diodes but soon as it turns on I hear a poping noise they short out.
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Old 04-17-2019, 11:00 AM   #5
Unspun01
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Default Re: tc-p50gt30

Again, please upload photos of YOUR board, and YOUR repair.

Did you replace all 6 IGBTs? Q401, Q402, Q403, Q421, Q422, Q423?

Are the IGBTs at Q621, Q622, Q623 ok?

Something is wrong. Re-test all transistors and diodes on the board before re-installing new ones. I think you might have missed other shorts that are on this board which caused re-failure.

Check also the low resistance gate resistors for each IGBT. I think they are 7.5ohm. If any are open then you need to replace.
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Old 04-17-2019, 03:12 PM   #6
tvtimmy
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Default Re: tc-p50gt30

Don't count out the possibility of using fake parts.
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Old 04-17-2019, 10:44 PM   #7
ricosavy
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Default Re: tc-p50gt30

Well after replacing transistors 3 times and them shorting out every time I powered the tv on.I checked resistors 8 ohms and also had replaced ic driver and transistor.I checked all caps,diodes and resistors they all tested good.
Saw tvtimmy on fake ones,tried another batch I have bought few months earlier they looked like better quality.Used them and the Sc board turn tv no more poping noise.Weird thing is a bought them from same supplier probably bad batch or fake.
Thanks for all your help.Tv is now working.
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Old 04-18-2019, 07:17 PM   #8
tvtimmy
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Default Re: tc-p50gt30

Can you post a pic of the bad and the good?
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