Samsung LN46A550 gamma question

[DLinkOZ]

At this point I'm very familiar with the issues surrounding the AS15 chips. This TV has the AS19 chip, which I also understand is the big brother as it has more gamma channels. I have this TV with the AS19 and the typical color issues with a faulty gamma chip. However, the voltages don't draw a line that's too terribly out of whack (see image). Is this enough variance to cause color distortions?

[DLinkOZ]

Re: Samsung LN46A550 gamma question

Pics of the color distortion.

[DLinkOZ]

Re: Samsung LN46A550 gamma question

I'm going to roll the dice and have the gamma IC replaced on my t-con. The voltages don't look terribly ugly, but the picture just screams bad gamma IC to me.

[budm]

Re: Samsung LN46A550 gamma question

I would too, you are right that it does not look that ugly but may be bad enough to affect the pictures.

[DLinkOZ]

Re: Samsung LN46A550 gamma question

Before I get it repaired, I have this constant little thing in the back of my mind when I look at the t-con. This is what's in my TV:

http://www.shopjimmy.com/samsung-bn8...-con-board.htm

And the service menu had it set as a 40" model, but this is a 46" set and SJ shows that only for 40" models. When I look at SJ for t-cons that work with this particular TV:

http://www.shopjimmy.com/catalogsear...=63&q=ln46a550

I don't see this one. Is it possible that the person I bought it from had a gamma failure, but without knowing what they were doing purchased the incorrect board? Perhaps based upon the V520H1-C06 number, which is common to both? Is there any way to absolutely confirm which part number I should use for the t-con?

**EDIT**
Also, when I opened it up the cover that goes over the t-con was missing, further leading me to believe that there was some monkey business going on.

[budm]

Re: Samsung LN46A550 gamma question

I believe the correct PCBA numbers are the one on the BARCODE, the printed numbers on the board is usually the blank PCB numbers which can be stuffed with parts for particular PCBA, so blank board can be used in many screen versions.
You should get the LCD panel number and contact SJ to see what they think.

[DLinkOZ]

Re: Samsung LN46A550 gamma question

I haven't been able to find the label for the panel, could it be under the bezel somehow? And yes, I used the number on the barcode to identify what was in my TV now and that SJ lists it only for 40" models. My thought was *maybe* the previous owner didn't know this, matched up the silk screened pcb number and here I am.

Thanks for the input, I'll keep trying to locate that stupid label (first time it has not been readily visible to me).

[budm]

Re: Samsung LN46A550 gamma question

Is your TV is LN46A550P3FXA?

[DLinkOZ]

Re: Samsung LN46A550 gamma question

It is, and I found the panel stickers, they were under the large black bar that has the wall mount threads.

[budm]

Re: Samsung LN46A550 gamma question

Well, it is your lucky day, I am burning this model and the others (and also LN32A550, 37A550) right now for 2 weeks now, it will not power up and cycling on and off, replaced cap on the main board fixed the problem.
So let me open it up again to get the T-CON info and the pictures for you.

http://s807.photobucket.com/user/bud...in=true&page=1

[DLinkOZ]

Re: Samsung LN46A550 gamma question

That would be awesome, thanks! SJ shows only 35-D025860 when searching by the panel number. Once I get this squared away, the only other thing I'll need (hopefully) is the panel type to plug in on the service menu due to it currently being set as a 40ac (I believe it was ac, but definitely 40).

[budm]

Re: Samsung LN46A550 gamma question

Here are the pictures of my LCD panel (SONY/SAMSUNG panel) and the T-CON.
I cannot believe your same model as mine uses the CHIMEI screen instead of the SAMSUNG.

[DLinkOZ]

Re: Samsung LN46A550 gamma question

Yeah, pretty strange. I'll get in touch with SJ, though they seem to be out of stock of the part I need. Searching for my panel number gives me this:

http://www.shopjimmy.com/catalogsear.../?q=v460h1-l05

And only returns one t-con, so at this point it seems to be pretty clear that I've got the wrong t-con in here. I emailed the seller, just asking if he still has it lying around (I'd love to get it and replace the gamma IC, if that was the original issue).

**EDIT**
Ok, so the search results in two boards. But the second is physically different, so would not be able to fit my set.

[budm]

Re: Samsung LN46A550 gamma question

So same model may use Samsung, AUOPTO, or CHIMEI screen.
http://www.shopjimmy.com/samsung/ln46a550p3fxza/

So your uses this one: for screen V460H1-L05 REV C1
http://www.shopjimmy.com/cmo-35-d025860-t-con-board.htm

[saddle_au]

Re: Samsung LN46A550 gamma question

Well, it is your lucky day, I am burning this model and the others (and also LN32A550, 37A550) right now for 2 weeks now, it will not power up and cycling on and off, replaced cap on the main board fixed the problem.
So let me open it up again to get the T-CON info and the pictures for you.

http://s807.photobucket.com/user/bud...in=true&page=1

May I ask, what is the main board, what cap failed and how did you find it?

[DLinkOZ]

Re: Samsung LN46A550 gamma question

While SJ wasn't able to absolutely say "yes, the 35-D025860 is the part you need," they were able to confirm the logic being used to arrive at that decision. So I'll keep an eye out for an inexpensive used one, since I don't have the proper board for a proper repair. Then I'll have a reasonable TV for one of the spare bedrooms at a good price.

And tonight I picked up a nice TV for the master bedroom, but that's a topic for a new thread!

[budm]

Re: Samsung LN46A550 gamma question

@saddle au: see https://www.badcaps.net/forum/showth...490#post517490

[DLinkOZ]

Re: Samsung LN46A550 gamma question

I picked up a faulty t-con from ebay for dirt cheap because it had "color issues." This time it's the correct part, not the 40" version that the previous attempted to repair the set with. My plan is to replace the gamma IC once it arrives. USPS lost it, should have been here a week ago so I called yesterday and they opened a case to find it. Today, less than 24 hours after opening that case, its tracking shows it at my local PO so happy days. Hopefully I'll *finally* get this guy going again.

[DLinkOZ]

Re: Samsung LN46A550 gamma question

Bad t-con arrived, and yep... that's an UGLY graph! I've never seen one so bad. Now for that replacement gamma IC.

[DLinkOZ]

Re: Samsung LN46A550 gamma question

Finally got the board repaired, and the gamma voltages are back to normal. A bit of a drop in the middle, but it must still be within spec as the picture is good. Now to get it hung in my younger son's room, he's already stated that he wants it to replace his 42" Panasonic plasma (my $29 TV - https://www.badcaps.net/forum/showthread.php?t=38935 ).