Samsung LE37R87BD

[sparkman001]

I know there are a lot of faults listed re this model Sammy but I havent seen this one before. The set works with a good picture, then about half an hour later the contrast will begin to advance by itself to 100%. You can reduce this in the menu, but again after a short while, it will increase once again.
Now, my instincts tell me faulty EEPROM, but before I embark on a wild goose chase, has anyone had this or a similar fault before.
Many thanks
Bill

[downunder]

Remove the t-con cover. Is there an AS15G [or F] on the t-con, small square 48 pin ic? If so, hit it with freeze when the picture gets bright. Picture back to normal - replace the ic.

[sparkman001]

Thanks Downunder, I'll have a look at that, but I rather doubt that a fault on the tcon board would alter the software values in the menu, which is what makes me think EEPROM
Cheers
Bill

[Kilroys]

I agree with Downunder, but I changed the T-con card BN81-01909A

[sparkman001]

Hi, thanks to those for the replies. This is a fault I haven't encountered on this model before, and I don't want to swap the tcon needlessly. I'm going to try a new eeprom first and will let you all know the outcome. Kilroy, did you have the same symptom? or are you going from gut feeling ? Personally I can't see how a fault on the tcon could alter the values in the menu.
Bill

[downunder]

If, as you state, the set works fine for 1/2 hour, how do you infer the eeprom is corrupted. If it is corrupt, it stays that way until it is corrected by external intervention, such as a factory reset. You could go into the service menu and execute a reset in the opening page but I suspect it'll do bugger-all.
I didnt ask you to replace the t-con, but just to verify the ic is there and check if it reacts to cooling down.
At least then you will know it's cactus. No gut feelings in this. It is a common fault with t-cons.

[sparkman001]

Downunder, please dont take this the wrong way, I dont doubt your expertise, we are all engineers trying to scatch a living, and unnesessary work or expenditure is something we can all do best to avoid, and Im gratefull for your input.
In the UK, as Kilroy has said he replaced the board, very often its cheaper, and faster to just replace the board. Simple economics. Ordering a special ic,postage/ handling, doing the SM rework is something I can do, but its time consuming and more often than not, not cost effective. It may be different where you live but here, everything depends on cost.
Regards
Bill   
   

[downunder]

No offence meant, Sparkman, and I agree with your sentiments re cost of repairs. But the punters have very short pockets and to me a $2 chip beats $xx for a t-con. Price of boards is strangling us here.
Keep sparking on.

[Kilroys]

Yes I have had one of these, but I cant remember if
it changed the value in the menu.
I hope you checked that it is not in "SHOP Mode"

[markc]

For what it's worth: I don't think it's the eprom or the T-con. If the actual contrast value is changing then I would suspect micro. As sparkman001 says, can't see the T-con changing that value & as others have said, an eeproms content is fixed, until changed by something else!
Please post the solution if you find it.

[marky mark]

Hello all, looks like you need to isolate the board before ordering anything


do the graphics come on when the contrast advances?