Samsung le40b655 makes high pitched noise, then turns off - no picture

[Coconuts 500]

Hi!

I have a Samsung le40b655 TV that doesn't work right. Here's what it does after you plug in power:

Indicator LED turns on, red.

If you press the power button, the LED starts blinking red for a few seconds, and then the backlight turns on (but the screen remains black) and you can hear a faint high pitched whine. After about a second, the lighting turns off and the whine stops. The red LED keeps blinking once or twice, then turns off altogether as if the power is away completely.

If you press the power button now, the LED turns on again. And now were back on square one.

I've opened it up and everything looks pristine. No visual signs of damage, and all caps LOOK fine. They're mostly Sam Young, and mostly aren't installed in hot areas (such as next to heatsinks). Bigger caps are Samwha and also look fine.

This feels like a bad caps problem but also not. Are the symptoms familiar to any of the experts around here? Thanks a lot for your time.

PS: I've included a bad pic of the power supply.

[Coconuts 500]

Re: Samsung le40b655 makes high pitched noise, then turns off - no picture

I've done some testing.

Main caps measure about 310V across each. They do hold their charge when the power is unplugged. It trickles very slowly away.

5, 13 and 24 V supplies all measure correctly. I've not tried loading them yet.

All semis (transistors, diodes, etc) semi-tested and appear fine.

I only saw two fuses and both are fine.

[saddle_au]

Re: Samsung le40b655 makes high pitched noise, then turns off - no picture

Check for a short to case with the tubes.

I had one where some insects had decided to move in and it sounded like what you described.

Disconnect the internal tubes and run a test on some external ccfl bulbs (as mentioned here in other posts, look up inverter testing).

[selldoor]

Re: Samsung le40b655 makes high pitched noise, then turns off - no picture

Please update your profile with country and mains voltage.
Please post a Good clear picture of your boards

[budm]

Re: Samsung le40b655 makes high pitched noise, then turns off - no picture

I've done some testing.

Main caps measure about 310V across each. They do hold their charge when the power is unplugged. It trickles very slowly away.

5, 13 and 24 V supplies all measure correctly. I've not tried loading them yet.

All semis (transistors, diodes, etc) semi-tested and appear fine.

I only saw two fuses and both are fine.

That Voltage is too low, this board has PFC Voltage booster so when the PS_ON is applied the Voltage on the caps should be >360VDC. Please verify the reading. What is you AC line voltage?
Diagram provided by tom66.