Bad driver(s)? Sharp LED TV

[scuby]

Re: Bad driver(s)? Sharp LED TV

you are referring to a chip on the tcon.... I was referring to the main board. You have checked / played with 2 tcons with "no good results" that is why I am suggesting moving on up to the main board as opposed to doing much more in tcon land at this point.

I'm leaning in a similar direction. Not knowing enough about how these things are put together I suppose I can't rule out the panel although to me I would expect other failure symptoms: half of the panel or a portion or image distortion etc. Not such clean and simple failure.

As soon as the TV is 'playing' anything the blue disappears. That paired with the dimming and trying two t-cons has me leaning towards some sort of chip failure on video processing. I'm hoping so.

[scuby]

Re: Bad driver(s)? Sharp LED TV

but I am not sure of this "statement"... you posted a picture of the "old card" versus "new" and they don't look the same at all.

I'll take your experience over internet speculation

[budwich]

Re: Bad driver(s)? Sharp LED TV

I'll give that a shot. There's a chip labelled: Pixel works Motion Engine which looks to run to the LVDS. I'll heat that. and observe.

I'll see if I can't find that fuse...

you are referring to a chip on the tcon.... I was referring to the main board. You have checked / played with 2 tcons with "no good results" that is why I am suggesting moving on up to the main board as opposed to doing much more in tcon land at this point.

[budwich]

Re: Bad driver(s)? Sharp LED TV

btw. from what I've read about the P8404 connector is that it's a specific power source for 3d. The 12v for the Tcon such run through the LVDS..

Yeah they saved precies pennies avoiding printing on these boards...

you have not posted any picture of the back to show how things are connected so one can only guess at "unlabelled" boards based on "connector familiarity"... that's a connector that I have seen on the tcon that provides 12v in, at least on some set. :-)

[budwich]

Re: Bad driver(s)? Sharp LED TV

Ok. Once the kids are in bed I'll check the LVDS for breaks/continuity.

I'm as sure as I can be that I'm seating that cable correctly. Also since removing it and reseating it the symptoms are all the same as before I touched it.

but I am not sure of this "statement"... you posted a picture of the "old card" versus "new" and they don't look the same at all.

[scuby]

Re: Bad driver(s)? Sharp LED TV

btw. from what I've read about the P8404 connector is that it's a specific power source for 3d. The 12v for the Tcon such run through the LVDS..

Yeah they saved precies pennies avoiding printing on these boards...

[scuby]

Re: Bad driver(s)? Sharp LED TV

you might try "slight heating" (hair dryer) on the mediatek chip on the main board to see if anything happens / changes... even subtly. A "quick look" appears to shows that the lvds signals basically leave that chip thru some "buffers" to the cable.... if my "inexperienced eyes" are correct.

I'll give that a shot. There's a chip labelled: Pixel works Motion Engine which looks to run to the LVDS. I'll heat that. and observe.

I'll see if I can't find that fuse...

[scuby]

Re: Bad driver(s)? Sharp LED TV

they are usually "micro fuses" that are "smd'ed" to the board. ***** added ***** there appears to be one fuse in the corner at p4804 connector which I assume comes from the power board.... its a larger SMD component between two "islands"... but that's just a guess. You can likely trace that connector back somewhere to power if need be. *******

You might do a "trace" of 12v at the power board to the main board and then to the tcon.

I think I watched your video of the set that you posted. I am thinking the problem is more with the main than the tcon... but maybe cabling especially since the 2 tcons work differently. Are you sure that you are seating the lvds cables between the main and tcon well / correctly?


I see tracing could be tough as this "fzcxvz" company decided to save money on label paint ... :-(

Ok. Once the kids are in bed I'll check the LVDS for breaks/continuity.

I'm as sure as I can be that I'm seating that cable correctly. Also since removing it and reseating it the symptoms are all the same as before I touched it.

[scuby]

Re: Bad driver(s)? Sharp LED TV

My walk through of what I've done so far

[budwich]

Re: Bad driver(s)? Sharp LED TV

you might try "slight heating" (hair dryer) on the mediatek chip on the main board to see if anything happens / changes... even subtly. A "quick look" appears to shows that the lvds signals basically leave that chip thru some "buffers" to the cable.... if my "inexperienced eyes" are correct.

[budwich]

Re: Bad driver(s)? Sharp LED TV

they are usually "micro fuses" that are "smd'ed" to the board. ***** added ***** there appears to be one fuse in the corner at p4804 connector which I assume comes from the power board.... its a larger SMD component between two "islands"... but that's just a guess. You can likely trace that connector back somewhere to power if need be. *******

You might do a "trace" of 12v at the power board to the main board and then to the tcon.

I think I watched your video of the set that you posted. I am thinking the problem is more with the main than the tcon... but maybe cabling especially since the 2 tcons work differently. Are you sure that you are seating the lvds cables between the main and tcon well / correctly?


I see tracing could be tough as this "fzcxvz" company decided to save money on label paint ... :-(

[scuby]

Re: Bad driver(s)? Sharp LED TV

Are you getting about 12 volts on each side of the fuse on the tcon, red probe on each side black probe on metal chassis.

I can't locate a fuse... looking for a standard cylindrical fuse yes?

[scuby]

Re: Bad driver(s)? Sharp LED TV

I am thinking your problem is up from the tcon. In post 20, the one picture with the blue "quarter screen" appears to show "part" of a display "icon"... that potentially being maybe something like "no signal check cabling" box that appears on some sets in the middle of the screen... look at your picture... you can see a small corner of the "box" in the "middle / center portion".

Perhaps you might take a closer look at the lvds cable and connectors at both ends visually. If possible, you might see if you can do a continuity test on the cable ... tough but doable with some small pins on the probes or otherwise.

One other point... have you checked any other input types?

Good idea on testing the cable. I will do that tonight. I have not tried any other inputs if not simply because I am not getting a menu or anything.

I'll try the other HDMI inputs. Idea being that perhaps they may show even more of a picture or something?

[nomoresonys]

Re: Bad driver(s)? Sharp LED TV

Are you getting about 12 volts on each side of the fuse on the tcon, red probe on each side black probe on metal chassis.

[scuby]

Re: Bad driver(s)? Sharp LED TV

Hmm. So the Tcon communicates back with the main board? As the dimming is of the LED's.

Here I made a video. Hope that helps gives some clarity as well as maybe spark some more testing ideas.

I can get a mainboard cheap enough in China. Good used for 24 dollars. Takes two weeks to get here. Might just order one up.

It just seems like there is NO video signal getting through.

[budwich]

Re: Bad driver(s)? Sharp LED TV

I am thinking your problem is up from the tcon. In post 20, the one picture with the blue "quarter screen" appears to show "part" of a display "icon"... that potentially being maybe something like "no signal check cabling" box that appears on some sets in the middle of the screen... look at your picture... you can see a small corner of the "box" in the "middle / center portion".

Perhaps you might take a closer look at the lvds cable and connectors at both ends visually. If possible, you might see if you can do a continuity test on the cable ... tough but doable with some small pins on the probes or otherwise.

One other point... have you checked any other input types?

[budwich]

Re: Bad driver(s)? Sharp LED TV

All of the following tests were done with signal input as verified by the audio playing. Not once did any image display.

Along the bottom edge of the TV there are 4 larger white ribbon connectors. Disconnecting the left side connectors result in 1/4th of the screen displaying fully white from top to bottom. Disconnecting the right side the same.


Along the bottom left and right side and in the far left bottom and right corner there are smaller ribbon connectors. The best I could do without fear of damaging something was to unclip them. Removing them seems like damage is inevitable.

Unclipping them had no effect on anything.

On the topic of "dimming" I noticed, as I was streaming youtube clips, that: in between clips when the video signal goes black on a working tv that the LED backlights also respond to this, much the same as the aforementioned darkening if there is no input.

So the LED's are getting some information about video signal at least.

The connectors all look healthy btw, no heat or anything of note to be seen.

Please see attached pictures for reference.

If I understand your reference to the "four white connectors" and the disconnecting... it appears to give a "1/4" screen white... this indicates a totally isolated quarter "panel" which only relies on "common voltages / grounds" to cause the LCD pixels to "transmit" backlight while the rest of the panel should be doing its "normal job". This allow the tcon to fully drive the panel and "usually" takes out a portion of the "duplicate side drivers" (depending on which side) along with some of the bottom drivers.

It still has not fully pointed the finger yet because it is possible that the tcon signal is not getting into the edge board because of a missing component voltage either not in the tcon (likely not because you have tried 2 boards) or because a component at the edge board is fubarred.

You are getting closer... I think to ascertaining things.

[budwich]

Re: Bad driver(s)? Sharp LED TV

Unfortunately there is no information on the Tcon board.

I can probe the pins but I'm not going to know what's what obviously.

potential next step?

so you are saying there is not "labelling" on the tcon anywhere? don't expect to see "12v" or things like that... more in terms of "names" that "suggest" an important "pin/location/testpoint". The same applies to the bottom edge boards. :-(

Your views appear to be limited exposure to the edge boards... I do believe some of the framing / bracing / members can be removed a bit to get easier access to things. Not sure it would help.

Further your other post about dimming and signals and button pushes is interesting.... potentially indicating a main board problem BUT I think some of the dimming is associated with tcon as opposed to the main board.

Further back to labelling, there is also likely some on the main board, perhaps there are some of interest there that can be checked.

[scuby]

Re: Bad driver(s)? Sharp LED TV

All of the following tests were done with signal input as verified by the audio playing. Not once did any image display.

Along the bottom edge of the TV there are 4 larger white ribbon connectors. Disconnecting the left side connectors result in 1/4th of the screen displaying fully white from top to bottom. Disconnecting the right side the same.


Along the bottom left and right side and in the far left bottom and right corner there are smaller ribbon connectors. The best I could do without fear of damaging something was to unclip them. Removing them seems like damage is inevitable.

Unclipping them had no effect on anything.

On the topic of "dimming" I noticed, as I was streaming youtube clips, that: in between clips when the video signal goes black on a working tv that the LED backlights also respond to this, much the same as the aforementioned darkening if there is no input.

So the LED's are getting some information about video signal at least.

The connectors all look healthy btw, no heat or anything of note to be seen.

Please see attached pictures for reference.

[scuby]

Re: Bad driver(s)? Sharp LED TV

Unfortunately there is no information on the Tcon board.

I can probe the pins but I'm not going to know what's what obviously.

potential next step?