Samsung PS42A410 has sound but no picture

[tom66]

Re: Samsung PS42A410 has sound but no picture

OK, you found a fault!
Please unplug the buffer board and see if the readings settle or if they are still bad.

[nick1969]

Re: Samsung PS42A410 has sound but no picture

Excellent, Thanks for helping i feel we are making progress

Removed buffer and powered up still 9 volts on VSCAN and VSCH same jumping around 40v mark as before

[tom66]

Re: Samsung PS42A410 has sound but no picture

So you probably have a bad Y-main board and maybe a bad Y-buffer.

You should test your buffer board. Here is how to do a test:
https://www.youtube.com/watch?v=51SZsfH60EY

[Ltank]

Re: Samsung PS42A410 has sound but no picture

So. When checking SMPS voltages you have the standby voltage and the 15 CDC but no high voltage?
There are feedback voltages to the SMPS. Turn off power, wait several minutes for capacitors to discharge. Use your DVM and check for a short across the HV dcv input to the Y or SC. Board. If OK check for short on the Z board. Once the faulty board is located, it can be trouble shooted to component level.
Ltank

[tom66]

Re: Samsung PS42A410 has sound but no picture

So. When checking SMPS voltages you have the standby voltage and the 15 CDC but no high voltage?
There are feedback voltages to the SMPS. Turn off power, wait several minutes for capacitors to discharge. Use your DVM and check for a short across the HV dcv input to the Y or SC. Board. If OK check for short on the Z board. Once the faulty board is located, it can be trouble shooted to component level.
Ltank

There are no shorts on the Vs on this panel as there is 208V going to the Y-main, so detailed analysis of the Y-main is necessary to determine where the fault is.

[nick1969]

Re: Samsung PS42A410 has sound but no picture

Thanks so much guys
Ok I checked the buffer And there doesn't seem to be any shorts
I did find something strange the VSCAN solder tab where I tried to measure the voltage from that was showing 0 volts goes to ground
Here's a picture from the solder tab labeled VSCAN on the Y board

[tom66]

Re: Samsung PS42A410 has sound but no picture

Yeah, the 0V there is bad.

[storexxm]

Re: Samsung PS42A410 has sound but no picture

Yeah, the 0V there is bad.

Hello. Did you solve the Problem?
I habe the same issue.. black screen with sound

[storexxm]

Re: Samsung PS42A410 has sound but no picture

please can someone help me?
i swapped cm402, cb402, cm408, cm405, cm401 and cb801
after putting it together it worked for an hour.
then back to clicking sound and no screen just audio.
then swapped cb809, cb808, cb807 and cb806
no change any more...
any suggestions?
please