Sony KDL-40HX700 Overvoltage Error APS-254

[Noah]

Hi guys!

My Sony LCD TV KDL-40HX700 has broken!  If I turn it on, it works fine for about 10 minutes or so but then it goes to standby. The red standby light flashes 7 times and the pauses and then again 7 flash and so on... After a bit of googling i figured out that 7 times flashing is a internal overvoltage error.
I opened the sucker up and checked the caps for shorts but it seems that all are good. The power supply board is the APS-254.

Does anybody ever had the same issue? I couldn't find any service manual or schematics. My next steps would be to check all voltage rails, but before that i wanted to ask, if anybody had the issue before.

Thanks!!

[SeanB]

How old is the unit, the CCFL lamps could be at end of life and thus needing higher voltage to light, which trips the overvoltage circuit in the inverter.

Check supply voltages from the power supply, and look at the backlight and see which driver they use and find the datasheet and find the overvoltage output and measure that as well.

[Noah]

Thanks for your reply! The TV is about 4 years old I think this isn't too long now..? I'll now check the voltages for the mainboard and the unregulated 24V for the Backlight. If they are good i have to tear it down a bit more...

[Noah]

Okay i checked the voltage rayls and they are all good.

There are 3 wires comming from the mainboard to the power supply and forwarded to the backlight board:

BL-ON
Dimmer
BL-Err

and the BL-Err is constant on 3.3V when i turn it on and then it goes straight into stby so i think the error IS comming from the Backlight board. This is the Board:

http://www.shopjimmy.com/samsung-lj97-02541a-backlight-inverter.htm LJ97-02541A
and the controller on it is labeled SSI091ASN i couldn't find a datasheet for it.

I think my repair ends here or i buy the replacement...