Philips 65PUS6554/12 one time backlight flash

[crozoki]

Hello
I have Philips 65" TV (65PUS6554/12).
Problem is when turn on tv backlight flash only one time for about 1 second then turns off and display is dark but sound is there.
Sometimes TV turns on and work with no problem, had backlight and picture, but mostly Tv wont turn on backlight. Any idea where to start looking?

Power board TPV 715G9187-P01-008-001S
Main Board 715G9907-M01-B03-005K

[Sraros]

Re: Philips 65PUS6554/12 one time backlight flash

Did you disassemble already the panel? I assume it’s same TV I see the leds at the background.
If yes, then you can start by visual check and without a multimeter testing voltages method your leds.
The way I do it is record a slow motion video the leds of the panel.
If the LEDs are the problem, when you connect to power and the leds flash briefly, you will see which ones didn’t flash and there’s your problem. Suggested fix is to replace all the LED strips. LEDs going bad is an indicator they start to wear off so if you fix individually, there is risk other ones go bad soon enough and then you have to do the same repair again.

If you haven’t disassembled the panel, check first the voltages on the LEDs connector, while the LEDs cables being pulled off and post again.

[Sraros]

Re: Philips 65PUS6554/12 one time backlight flash

Oh and by the way, I recommend not to lay the boards on the diffuse sheets!
They can make scratches and create shadows and bright spots at your TV’s image!

[crozoki]

Re: Philips 65PUS6554/12 one time backlight flash

tnx for the tip.
i have disassemble panel reconect power board, main board and t-com without display. now backlight turn on every time.

[Sraros]

Re: Philips 65PUS6554/12 one time backlight flash

That’s great! Sth triggered the overvoltage/undervoltage protection for the LEDs inverter.
I hope it was sth trivial that got fixed by disconnecting and draining completely the caps, and it remains at working condition.
However have a go on different cases. Let the TV operate for a while to warm up and standby-turn on again or power off-on.
Somebody more experienced maybe can explain why this happened.

[crozoki]

Re: Philips 65PUS6554/12 one time backlight flash

tv operate for a while without display panel and backlight suddenly went off. reconect 220v plug but nothing hapen. backlight is off.

1. unplug connector of main board from power board reconect 220v plug nothing hapen
2. voltage on connector for mainboard is 10V but it should be 12 V
3. connect main board to power board and start messuring on connector voltages when conect 220v plug to power board on connector voltage start 12v and after few second voltage drop to 10v and strage noise cames from mainboard

[dskall]

Re: Philips 65PUS6554/12 one time backlight flash

Sounds like something is shorting. Unplug T-con.