Samsung LN46B640R3F NO PICTURE

[Redrebel10]

Reaching out once again to you TV gurus, I picked up this Tv from a friend and the picture worked great starting out but then would start becoming white washed, (negative image). After reading on here I decided to try and replace the as15 ic chip. So my limited experience caused me to fail as when I put it back together I lost the picture, I still had backlights but no more picture. I'm guessing I had bridged pins or incomplete solder joints on the pins. I then decide just to order a new tcon board. I got it today and nothing changed. I have backlights but no picture and nothing shows when pulling up source or menu. I disconnected the lvds from tcon to panel and I got words on the side still connected (though it was completely whitewashed). Got the exact same when I tried disconnecting the other lvds cable from the panel. Not sure where to start troubleshooting because I fear me messing up the as15 chip I may have caused another problem. Thanks in advance I will post pictures from my phone.

[Redrebel10]

Re: Samsung LN46B640R3F NO PICTURE

Here are the boards

[attainteddragon]

Re: Samsung LN46B640R3F NO PICTURE

i had a similar set recently and found liquid damage on the panel driver boards. of course i changed the as15 ship first, but, you get that.

i would remove the metal frame and inspect the boards just to be sure.

[Redrebel10]

Re: Samsung LN46B640R3F NO PICTURE

So break the panel down, do you have a write up on taking this panel apart to get to the boards you are referring to?

[zomi]

Re: Samsung LN46B640R3F NO PICTURE

Do you have 12v on the tcon fuse ?

[Redrebel10]

Re: Samsung LN46B640R3F NO PICTURE

I see no fuse on my tcon board, which one are you referring to using the picture I provided.

Attaineddragon, I'm not ruling anything out but keep in mind the tv had picture before I messed with the as15 chip

[attainteddragon]

Re: Samsung LN46B640R3F NO PICTURE

ok, lets start with the voltage readings of the vg test points. from 1 to 22 in dcv. they are next to the as chip. these are your gamma voltages and will let you know if your as15 chip is working properly.

[attainteddragon]

Re: Samsung LN46B640R3F NO PICTURE

your t-con fuse is f0002 and is just below the 4 pin connector to the t-con. i would expect it to be good though since you have partial screen operation.

[Redrebel10]

Re: Samsung LN46B640R3F NO PICTURE

these are the only test points I saw, grounded to chassis

1 7.3
2 7.8
4 7.8
6 7.8
8 7.8
10 7.8
11 7.6
12 7.1
13 7.2
15 9.3
17 4.9
19 12.9
21 15.7
22 15.8

[Redrebel10]

Re: Samsung LN46B640R3F NO PICTURE

12.4v on f0002 fuse

[attainteddragon]

Re: Samsung LN46B640R3F NO PICTURE

that is a bad AS chip. just out of curiosity, can you disconnect the ribbon cables that go to the panel and retest.

[Redrebel10]

Re: Samsung LN46B640R3F NO PICTURE

sure can

1 7.3
2 7.8
4 .01
6 2.6
8 7.8
10 7.8
11 7.8
12 7.1
13 7.2
15 9.6
17 1.1
19 13.1
21 15.8
22 15.8

[Redrebel10]

Re: Samsung LN46B640R3F NO PICTURE

bold are the changes with both lvds ribbon cables disconnected from panel

[Redrebel10]

Re: Samsung LN46B640R3F NO PICTURE

what are the facts on voltage readings proving it has bad as chip, partserve is where I bought the board and they will try charging a restocking fee unless the board is bad

[attainteddragon]

Re: Samsung LN46B640R3F NO PICTURE

unfortunately the voltages are still bad. the voltages should form a curve if graphed out and these results are far from that. looks like you got a dud board.

you can always link this thread to them to show that you have actually tested the board.

[Redrebel10]

Re: Samsung LN46B640R3F NO PICTURE

OK thanks

[Redrebel10]

Re: Samsung LN46B640R3F NO PICTURE

Attainteddragon can you post a link to the thread where you found damaged driver board or suggest what steps I should follow. I got another tcon board and its back to the original state before I ever touched it, gamma slightly off so I'm starting to think I may have another problem. I will tell the vgma on the newest tcon on Monday when I get home

[attainteddragon]

Re: Samsung LN46B640R3F NO PICTURE

unfortunately i didn't get any pics of the damaged driver board that i had from a few weeks back, and it looks like i threw the board out.

i'm not sure what other issues you could be facing outside of the as issue. maybe others might shed some new light on your set.

[Redrebel10]

Re: Samsung LN46B640R3F NO PICTURE

I guess its possible the 2nd used tcon board I bought has a bad ic chip, however my picture is slightly off, not near as bad as some of the associated pictures of negative images. I tried messing with all the settings with no luck. If there is anyone in the south that is up for letting me mail them my board that is willing to change the as15 chip.... Please let me know