Tuesday, February 16, 2010

Sony KLV-40U100M problem - dead, no picture, no sound, no power - 715T1723-J

A Sony KLV-400U100M LCD arrived in shop today with no signs of life - no LED on front panel and no response to any of the buttons whatsoever. Comletely dead.

One could hear a short buzz when plugging in outlet, though, so at least power board was showing some signs of life.

So it was either power board or main board.

Power board 715T1756-F was a bit difficult to understand without a schematic as it doesn't have any indication of what it should provide, but by looking at the back of board where the connector contacts were I was able to isolate the standby power which turned out to be 5V and available.

With a little guessing I could also figure the power on signal pin and upon signalling it with 5V through resistor I was able to bring up other voltages.

That ruled out the power board as a suspect and left the main board 715T1723-J as the prime suspect.

And indeed it was!

I'll eventually blog about what I learned as it will sure help some, but for the time being I have to go....sorry.

In the meantime, if you need your own board serviced feel free to contact me.


whatdaprblmis said...

how would i go about testing my board to determine what the problem is.

it seems as though what you describe is exactly the same as my current problem, any feedback would be greatly appreciated. thanks

toopure2000 said...

hello. I have two of these TV's with the same problem you resolved. Can you share the repair procedure for the main board? THANKS, in advance, for your insight and knowledge.

Faucon said...

hi, i have a power board 715T1756-F of that television that is broken. At the 120vAC input, the fuse is ok, 120vac is passing by the 3 coils correctly. just after the coils, there is a thermistor sck055 with an other green part that i cant see what it is. The problem is that the sck055 exploded. One of the lead made a 1/4" hole in the board. I did replace the thermistor by a equivalent. After those 2 parts, there is a D25XB 60 wich is a rectifier. With 120vac on the board, at the two center lead of the rectifier, i have a little 2vac and it keep going up very slowly. Like 2.1v, 2.2v, 2.3v. Am i suppose to get 120vAC at the center leads of the rectifier ?

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