SHARP LC-60E79U display goes from washed out very grainy to white

[Davi.p]

Re: SHARP LC-60E79U display goes from washed out very grainy to white

I think it can't be a gamma correction problem 'cause the image is variably blotched / stained, and also those stains are present with tcon flat cables disconnected, surely no gamma circuitry are on the edge boards, never seen so and no reason to be so..
another way to diagnose is to spray freezer on the tab drivers, especially those at the sides.. before this check the temperature on them, if too high spray can break them.

[shelby5041]

Re: SHARP LC-60E79U display goes from washed out very grainy to white

i do appreciate all the help

i really dont want to put much inot this tv...its not worth it nowadays

tvs are dispiosable........before i scrap it i just wanted to make sure it wasnt some other issue that can be repaired....

a bad panel for the most part is not repairable nor even worth the time nowadays

the reason why im stubborn is that a few yrs ago everyone told me my 50 zenith plasma tv panel was bad....i had 2 same models doing same thing and all responses were panel bad

well ....i stuck to my guns and it wasnt a bad panel it was bad buffer boards which i bought but were actually bad from shop jimmy.....but in the end i fixed both tvs which would have been tossed in trash

so it does seem bad panel here but i want to make sure 100%

or at least 99% lol

i really dont get into tvs anymore since its just not worth it to me.....now that new tvs are so cheap.dime a dozen....i used to tinker a lot but very little anymore..just trying to clean house on wanna b projects that need to be dealt with or tossed out...decluttering

[shelby5041]

Re: SHARP LC-60E79U display goes from washed out very grainy to white

i believe 2 yrs ago when i last worked on this tv i did look at the boards that are on bottom of tv and they were not touching any metal ..i think i even put some material in between to make sure and it did nothing....and i believe i did test power from ps going to tcon and it was good..and thats why i bought the replacement tcon board....which was used.....but we all know that buying used boards does not mean they are good....what i need to do is test the test points like the other guy said and if they seem ok then that would rule out tcon board

[shelby5041]

Re: SHARP LC-60E79U display goes from washed out very grainy to white

here is a photo of tcon from online ....what would i test and what voltages am i looking for...if anyone knows

[dick_barton]

Re: SHARP LC-60E79U display goes from washed out very grainy to white

Without a circuit diagram you could look at the voltages on the level shifter MAX17079 and see if they match or at least follow the expected voltages. Eg Vcc, VH1, VH2, Vcom, VL2, VL1, VLS as shown on the datasheet.

Also Sharp 200WNA1 regulator

[Davi.p]

Re: SHARP LC-60E79U display goes from washed out very grainy to white

I don't understand.. from a post seems that you don't want to investigate further, but in the next you ask for advices.. Which one is??
The card has no TP marked so has to be put a little patience, i have to read the MAX17126A datasheet, the voltages generator, i don't know the function of max17079... the other Maxim chip is difficult to read.. which one is gamma correction?

[Davi.p]

Re: SHARP LC-60E79U display goes from washed out very grainy to white

Anyway, (1,2) have to be around 16V, (3) 3,3v, (4) -6V (i have indicated the other terminal that is at gnd, sorry), (5) 27V...
Bye...