LA52A650A red standby light blinking, no clicks

[syaoran123]

LA52A650A (LA52A650A1F)
Wont turn on, red standby light blinking, no clicks, quiet squealing coming from the power supply not speakers.

After replacing with another power supply, the same thing happens.

I have now narrowed it down to the mainboard. I am getting 4.6 ohm reading on the 13V pin to GND and other pins tested fine. Im quite confident this is where the problem is. Can anybody tell me what component may need replacement? I cannot find the service manual online. Note the LN and LA lineup use different boards.

[budm]

Re: LA52A650A red standby light blinking, no clicks

The 13V is for the audio amplifier so there is possibility that the Class D power amp may be bad. Try disconnecting the speaker connector to see if the resistance reading on 13V pin will change.
Also try disconnecting all other connectors to see what if the resistance reading will change or not also.

[syaoran123]

Re: LA52A650A red standby light blinking, no clicks

The 13V is for the audio amplifier so there is possibility that the Class D power amp may be bad. Try disconnecting the speaker connector to see if the resistance reading on 13V pin will change.
Also try disconnecting all other connectors to see what if the resistance reading will change or not also.

Oh the testing was made while the mainboard was out of the TV. So everything was already disconnected.

[budm]

Re: LA52A650A red standby light blinking, no clicks

There are service manuals here, you just have to download them to find out which one has the schematic that matches your main board.
https://elektrotanya.com/showresult?...oria=&kat2=all

[syaoran123]

Re: LA52A650A red standby light blinking, no clicks

PROBLEM SOLVED!

Unfortunately, the link didnt contain a matching board to the one i have.

Fortunately, I managed to trace the shorted 13V pin down to a shorted smd capacitor on the back of the mainboard. Just a single capacitor change solved the entire problem. It was C1174 with a value of 10uF replaced with an electrolytic capacitor of 50V rating.

Hope this helps someone else.