bush DLED32165HDDVD with vestel 17IPS71 PSU

[john72]

Hi all, just got this TV on the table for repair thought it would be an easy one tho it might still turn out to be.

Complaint is no picture / Back light.

When you switch it on standby light flashes when you press power to bring it out of standby accompanied by a brief flash of the back lights then nothing.

I've checked diodes because the other tvs have usually proven to be either shorted diodes or bad caps.

All caps test bad on this board with my peak atlas ESR meter. They are either high ESR or gone high / low capacitance.

I'm fairly confident that they need changing and may well fix my issue.

However I've been checking some voltages at the LED connector and I see it starts high when the back light flashes on briefly then slowly ramps down. Then if I check the voltage on the negative side of the back light, it ramps down slowly.

I'm unsure if at this point I have a shorted LED or the PSU cannot supply the voltage and is shutting down to protect itself.

Only equipment I have at my disposal right now is the Eevblog BM235 and my peak ESR70 meter.

Any pointers as to what to check next would be greatly appreciated.

Thanks John.

Edit: Just to add that when checking voltages of the LED connector (CN6) red positive immediately jumps to around 45v when the back lights flash on and then slowly decrease. Black negative goes to about 80v and slowly decrease.