Samsung LN46A630M1F Gamma chip repair question

[Maxstang]

Hey everybody!

Working on an LN46A630M1F which had an obvious gamma chip issue. I changed out the AS15F chip with a used spare I had and the picture looks...ok now. The picture has an odd look compared to most Samsungs I've seen. Almost like it's not running full resolution. I even tried hooking up a bluray player to it so make sure it wasn't the tv signal, but it still looks strange. It's hard to describe and I can't really capture it on film. Objects seem to be like overlapping cardboard cut outs. I'm thinking the chip I used either wasn't good, or that I have a solder bridge or something. I've done this repair successfully before, and have tested my work by checking the Gamma test points. So here's my question: This T-Con board doesn't have Gamma test points that I can find. Is there another way to test the chip when running or does someone see a test point in my picture that I can't see? Thanks again!

[tom66]

Re: Samsung LN46A630M1F Gamma chip repair question

Try turning Just Scan picture mode on, and turning off Motion Enhancement in advanced options. Or enabling Game Mode.

[Maxstang]

Re: Samsung LN46A630M1F Gamma chip repair question

Thanks for the reply Tom. I've been through all the options in the menu and it still looks ...well...odd to me. I wish the dang thing had test points! I guess I can try and replace the Gamma chip with a new one again (what a pain) and see what happens.

[tom66]

Re: Samsung LN46A630M1F Gamma chip repair question

There are points marked VG1 thru VG18 (19, 20, 21, 22)... for gamma voltages

[Maxstang]

Re: Samsung LN46A630M1F Gamma chip repair question

Thanks Tom. I'm an idiot. I saw the list of test points before, but they're not near any actual pads. I figured it out today. I must have been tired from all that soldering last night. Anyway, the voltages ascend as they should, but the picture still seems a bit off to me, as if it's not full resolution.

[tom66]

Re: Samsung LN46A630M1F Gamma chip repair question

Did you record them? You giving it a Full HD 1080p source? It is a 1080p panel...

[Maxstang]

Re: Samsung LN46A630M1F Gamma chip repair question

Here are the voltages. Something else is going on as it suddenly stopped responding to the remote other than to turn it on.

VGAMA1 15.34V
VGAMA2 13.17V
VGAMA3 11.11V
VGAMA4 10.34V
VGAMA5 9.98V
VGAMA6 8.10V
VGAMA7 7.10V
VGAMA8 5.15V
VGAMA9 4.74V
VGAMA10 3.90V
VGAMA11 2.25V
VGAMA12 .38V

[tom66]

Re: Samsung LN46A630M1F Gamma chip repair question

Seems OK, try factory reset (MUTE - 1 - 8 - 2 - POWER from standby for service menu then select reset under one of the menus.)

[Maxstang]

Re: Samsung LN46A630M1F Gamma chip repair question

Seems OK, try factory reset (MUTE - 1 - 8 - 2 - POWER from standby for service menu then select reset under one of the menus.)

Remote suddenly started working again. It was strange, the red led receiver light didn't even flash when it wasn't working. Tried two different remotes. Front panel buttons worked fine although it looked like it was trying to scroll through the channels really fast at one point. Perhaps I have a stuck input.

Tried a factory reset. Still looks...well kinda weird. I appreciate all your help.

[Maxstang]

Re: Samsung LN46A630M1F Gamma chip repair question

I have another FRC board for this TV (didn't know my parts pile was that big). I'm going to try it out and see if it makes a difference.

[Maxstang]

Re: Samsung LN46A630M1F Gamma chip repair question

Just to close this out, I replaced the GAMMA chip again and the TV is fully working now. I think the used chip I had harvested and used was faulty in some minor way.