Sony KDL46S4100 backlight not working

[horn1991]

This TV was given to me by my brother. It quit working on him one day, and he just went and bought a new one.

I've searched and researched quite a bit so far. I decided to go for it and try a new main A board.

With it all hooked up, still no picture. I turn the TV on, and the green power light is solid.

If I unplug CN303 with the power on, the TV cycles through a green screen, a blue screen, a red screen, and then a striped screen. The striped screen is one quarter red horizontally, one quarter blue, one quarter green, and one quarter gray.

When I plut the connector in, the backlight goes off.

Any advice, thanks.

Dave

[anmol]

Re: Sony KDL46S4100 backlight not working

check inverter board

[tibimakai]

Re: Sony KDL46S4100 backlight not working

No blinking LED?

[horn1991]

Re: Sony KDL46S4100 backlight not working

nope, no blinking LED.

Not sure how to check the inverter board. I'll need to look that up.

[Mr Bill]

Re: Sony KDL46S4100 backlight not working

If you get everything hooked up where it will turn on (solid led), take a flashlight and shine it directly on the screen in a very dark room and see if you can find "no signal". I usually shine the light towards the bottom of the screen and hit the volume key in the keyboard.

[budm]

Re: Sony KDL46S4100 backlight not working

The inverter is working, otherwise you will not see it cycles through the RED/BLUE/GREEN screen.
It sounds like it's stucked in the test mode.

[horn1991]

Re: Sony KDL46S4100 backlight not working

yeah...it can definitely create a picture of some sort. The main board was damaged from a small water leak. just a few drops, but enough to foul several components.

I bought a new main board online...TSM electronics or something. Anyway, the cycling RGB occurred with the new board. But upon further inspection, I think they sent me the wrong part.

I've since sent it back, and hope to have the correct board sometime next week. Hopefully that will get it back to working.

[tom66]

Re: Sony KDL46S4100 backlight not working

With the old board, does it cycle test patterns as well? Accessing the service manual may give an option for turning off the test mode, or you can try resetting the EEPROM, a similar trick done on Samsung LCD TVs.

[horn1991]

Re: Sony KDL46S4100 backlight not working

no...the old board did not cycle anything. With the CN303 plugged in, the screen was dark. Unplugging CN303 on the old board would bring up the backlight, but not any color cycling.

[Silviyius]

Re: Sony KDL46S4100 backlight not working

You might be able to program the board if its the wrong one. might be a pain but you could do it. assuming you have the tools. What board is it?

[horn1991]

Re: Sony KDL46S4100 backlight not working

appreciate the offer...but I already sent it back. Found the correct board somewhere else (hopefully, if they send what I ordered). Cheaper, too.

I am a firm believer that the simplest explanation is the solution. I have a damaged Main Board from a water. No other damage is apparent. The correct main board should heal the TV. :-)