Sharp PN-R703 faulty Picture

[Wampo]

Hy,

what could be the problem?

T-Con Module is whistling!

Has anybody Schematics or Boardviews for this one?

Thanks Daniel

[attainteddragon]

Re: Sharp PN-R703 faulty Picture

looks like you might have a bad panel. can you feed a different source into it so we can get a better look.

[dskall]

Re: Sharp PN-R703 faulty Picture

Cracked screen

[Wampo]

Re: Sharp PN-R703 faulty Picture

Ahh i forgot to say... Screen is not Cracked!!! But it looks so i know.

The Picture just builds up very slow line for line

[budwich]

Re: Sharp PN-R703 faulty Picture

feed in a known test pattern... and if you have to wait for it to "complete"... then post a picture of the "end result".

further: if you want further help, post clear pictures of the boards and back of the set layout.

[dskall]

Re: Sharp PN-R703 faulty Picture

Disconnect ribbon to panel cable one at a time and see what changes

[Wampo]

Re: Sharp PN-R703 faulty Picture

I have take some pictures and i found another new failure.

If i take Brightness to 1 the Picture looks with a white silk over it and its very slow. (pic 3734)
If i turn up the Brightness to max then the colored stripe or blopp appears in the left upper corner (pic 3732)

The Stripe in the Middle is always there, but its not the ribboncable, i have pushed it on the glas and pcb side.


I have take detail pictures from the t con board. The chip makes some noise, like a mosquito. I have changed the Tconboard but the failure with the blopp is the same.



Sorry for my technical bad english ....

[attainteddragon]

Re: Sharp PN-R703 faulty Picture

bad panel i'm afraid. tab bond failure. you may be able to do a patch job, but nothing permanent.

[Wampo]

Re: Sharp PN-R703 faulty Picture

But why the blopp is just visible or comming on high Brightness?

I think it must be some Voltage Drops or something else?!

[budwich]

Re: Sharp PN-R703 faulty Picture

it is likely that a tab driver is loading down the "lines" of the other drivers. Look at the lower corner of the panel (on each side). There are small flex cables connecting the lower edge boards to same side edge boards. These are boards drive the tab drivers so to speak. At the flex cable on the left side (looking at the screen), with power off, disconnect that cable (unclamp it) from the connector / holder. See if anything changes on the display.

[Wampo]

Re: Sharp PN-R703 faulty Picture

Do you mean the Corner Flex Cables?! (top and bottom)
these cables conect the horizontal and vertical lines, is this right?!

The horizontal lines are connected from one side to the other?

[Wampo]

Re: Sharp PN-R703 faulty Picture

OK now i have disconnect the upper corner ribbon cable from picture. the screen works, BUT:
1. also the big vertical bar in the middle
2. mainchip on tcon dosent whisteling
3. faster responsetime (no picture delay or build up time)
4. also have the whithe silk over the screen, very pale

also i have a new failure, if i reconnect the ribbon after power down, i just got a black screen with the big vertical bar in the middle and the picture gets brighter but veerrrrrryyyyyy sloooooowwww....and the image isnt showing

just the gohst shadows

[budwich]

Re: Sharp PN-R703 faulty Picture

sorry but I am not sure I understand what you are saying / done. The picture that you refer to has "circles everywhere". :-)
are you using your glasses when you are working with these cables???? you have to make certain that they are seated properly at all times.

go back specifics... specifically, disconnect the one corner cable that I suggested, feed in a known test pattern (color bars or otherwise from a source like a dvd special features or otherwise... lots of these around).... post a picture of the results. Go from there... BUT it doesn't look good as it appears based on what I think you did, that the screen has tab driver issues..... further BUTT :-) it might be saveable to some degree.