Re: Sony KDL-40s4100 No Picture/Sound/Backlight

Since *repairing* the TV, one problem has raised it's head. Now, whenever the TV is switched off, the TV forgets all it's channel information. I would think that info is stored in RAM? If so, I wonder if both problems were related?

Isn't this fun

Thanks for the input guys....

Re: Sony KDL-40s4100 No Picture/Sound/Backlight

Just as an update:

I reassembled the TV, attached an antenna and powered it up. Perfect picture and sound! Was it a bad cable? I don't know as I couldn't get it to quit again. It's been on for about an hour and a half with no issues.

Being a technician, I worry about repairs that I don't know what fixed it I think I'll use it as a shop TV for a few weeks before giving it to my son.....

Re: Sony KDL-40s4100 No Picture/Sound/Backlight

This is weird, and I have no way of explaining it! Looking through the schematic, I found CN2502 on the A board, and it contained most of the back light signals. I unplugged it and the back light came on. Of course, I checked for video and of course there was nothing.

I power cycled the TV with the connector back on, and low and behold, the tv powered up with picture and sound

I'm so confused

Hi Guys:

I just acquired a used Sony KDL-40s4100 LCD TV with no picture, sound or backlight. The power light IS on and can be controlled with the remote.

I've checked all the voltages from the G (power supply) board and they are all OK. From what I've researched, everything points to the A (Main) board, but I have one question. Wouldn't the backlight (inverter) come on even if the A board was faulty, or does it control the backlight as well?

I've even gone to point of checking all the regulators on the A board, and
they all show what they are...