Samsung 37LEC550, some questions about my diagnosis

[ringsgold]

Hi, I'm trying to fix a Samsung LE37C550. (title has a typo) Service manual here

The power LED doesn't come on and the TV doesn't switch on.
All the caps on the power supply look fine, I've tested the output voltages. When the main logic board is disconnected the 24v, 12v and 5v all seem fine, with the logic board connected only the 5V standby is enabled. With the logic board disconnected the backlight switches on by itself.
The LED/IR/buttons PCB gets 3.3v. Measuring the button signals, they go from 3.3 to 0v when a buton is pressed. The LED_STB pin shows 0.78V (measuring GND - LED_STB) but the LED doesn't switch on, not sure what that means.

My diagnosis is that the main logic board is broken, since the buttons seem to work but the tv won't switch on. Some things I'm not sure about though: I haven't tested the power supply under load, and the fact the LED doesn't turn on (while it gets power) seems strange.

So my question is what else should I try to confirm the main logic board is the cause, and where can I buy a new one? The part number is BN94-03391J. Most of the shops google turns up seem kind of sketchy though, so I was wondering if you guys know a good one.

I'm planning to throw the old board into the oven first, see if a DIY reflow does anything.

[budm]

Re: Samsung 37LEC550, some questions about my diagnosis

"My diagnosis is that the main logic board is broken," You are correct, the main board is not sending the PS-ON signal to turn on the rest of the power supplies, and probably not the BL-ON either.

[ringsgold]

Re: Samsung 37LEC550, some questions about my diagnosis

Thanks, do you happen to know a good place to buy a replacement? I'm in the Netherlands.