Sony XBR65x930D - left half screen is grainy

[misterhaus]

Re: Sony XBR65x930D - left half screen is grainy

The 4 TCON cables from the TCON board to the edge boards are in place.

The only cable removed is the interconnect between the two right-side edge boards.

The photo was only showing the right side of the screen.

[budwich]

Re: Sony XBR65x930D - left half screen is grainy

hmmmm ..... this is strange. As normally, a white based picture occurs when one side of the tcon is totally disconnected (which you have seen). However, when the interconnect cable is disconnected, IF the problem is on the "disconnected portion" (ie. further down the signal line), the remaining "quarter" should show a picture that is as good as the other half which is fully connected (hope you follow). I would say that your problem possibly resides some where on the edge board closest to the middle that is still connected on the bad side.... although I haven't looked at the voltage readings post at this point. Did you checked the voltages again with the "disconnected U" setup?

[misterhaus]

Re: Sony XBR65x930D - left half screen is grainy

Looking at components on the edge board segments - the segments that make up “right” aren’t independently functional, I believe. For example, the outer most have two ICs (described above) and the inner ones don’t. So disconnecting an outer probably disables the entire half.

[budwich]

Re: Sony XBR65x930D - left half screen is grainy

I don't think that is true based on my experience. The reason for the difference has to do with how the panel is designed. In this case / panel, I don't think you will find edge board along the side BUT you will find tabs along the side. Hence, some of the "side edge board function" is provided by the "outer quarter" edge board at the bottom. I know that on sets with "multiple bottom edge boards" that they can be disconnected and IF everything is working correctly, you will get 3/4 panel functioning with a picture.

[misterhaus]

Re: Sony XBR65x930D - left half screen is grainy

I have added photos of the edge PCBs on the bottom of LCD panel - this is only the right half of tv.

I note that voltage test points are mostly on the inner-most PCB, not both boards.
Also, the ICs at outer most edge of outer board are not present on inner most board.

There are two pairs of boards at bottom edge of TV screen. Photos here are just the right side pair.

[misterhaus]

Re: Sony XBR65x930D - left half screen is grainy

More info on the LCD driver boards.
They are made by Innolux (aka ChiMei Innolux or CMI).
The model sticker for the set of boards is: V650DK6-QS1 (65 in model is for 65” LCD, I believe).

A data sheet on an older model with 4-sections (sections labeled XLL, XLR, XRL, XRR):
https://cdn.badcaps-static.com/pdfs/...1a3342642b.pdf

I've got my oscilloscope out and am checking various things. This is my first driver board diagnostic - so I'm not clear on my approach.

Any tips welcome!

[budwich]

Re: Sony XBR65x930D - left half screen is grainy

have you looked at the front of the panel with the plastic bezel removed? You will expose the tabs connection of the edge boards at the bottom to the panel itself. It is possible that someone may have accidentally "contaminated" those connections with "liquid" ("window washing effort"). Further, you then can confirm the existence of side tabs.

Having said that, based on your testing todate, I would say the problem is with the center right edge board... BUT I have seen problems on this forum with issues on the side that cause issues with the bottom drivers but not the "classical symptom" of horizontal lines appearing. As a result there is a slight chance that the side drivers of the panel are causing a problem BUT the disconnecting of the "U" cable should have removed their impact on the display.

[misterhaus]

Re: Sony XBR65x930D - left half screen is grainy

The bottom edge cover that I removed exposes the edge of the glass lcd panel. The ribbon cables are sort of epoxy potted onto the back of the glass. There doesn’t appear to be any windex damage - everything looks clean.

I did make a little progress. With the right-most lcd driver board disconnected, which puts VGH and VGL in normal range, I figured out by trial and error how to get the center half of the right side of screen to display as you expected. That means 3/4 of entire screen displays normally. It requires my finger to press over a capacitor or two on the right/center LCD driver board. (I put pressure on the C36 / C48 area to make the video appear in attached photo.)

It seems like it’s not the physical pressing (since I tried with a q-tip and it didn’t work), but maybe the capacitance of my finger. I believe it’s the timing signals that I’m pressing on. If I reconnect the right-most driver board then I don’t need to press on the capacitor to get the screen to display. But it’s grainy on the entire right half (original symptom).

I’m not sure if a capacitor is out of spec (can’t find a schematic).

[budwich]

Re: Sony XBR65x930D - left half screen is grainy

Sooooo..... you are heading in the right direction. As you have discovered that the problem appears to exist with some SMD components on the edge boards. Others have "spotted" shorts in the caps on these boards.... although not easily as some / most of the caps are in parallel, hence a short in one will measure a short across all.... they have to remove one at a time to determine which is bad... painful work. In your case, it appears that perhaps, in your case, one of them is "weak" / leaky and that the capacitance of the "set" is not as expected resulting in the response that you are seeing.... maybe. One other thing that you can try, is to connect everything back up and do your "touch of capacitance" on the area of interest and see if it gets you a better overall picture and go from there. One thing, be careful when playing with the unclamping / reclamping of cables as they can be damaged relatively easy along with misaligned along the way.

[misterhaus]

Re: Sony XBR65x930D - left half screen is grainy

Update after a few days of intermittent investigation. I think I'm getting closer.

See pic below, showing the XRR (far right of the LCD panel Driver boards labeled XLL, XLR, XRL,XRR). This shows a strange very low resistance measured between CK6_I and VGH.
Typically I would be checking resistance to ground, but in this case I was tracing the VGH signal which seems to be pulled low due to some problem. (VGH reads 30V when XRR driver board is disconnected, but lowers to +0.57V when XRR is plugged in.)

The image here shows my measurements.


Zooming out, here's a larger shot of this side of the XRR board.


I'm wondering if this could be the IC (U3) near these CK1-6 pins, or if it is the COF IC (on ribbon cable) or if it's the LCD panel itself.

I'm not familiar with LCD panel failure modes and am trying to theorize what would cause the cross-over between CK6_I, CK5_I (lesser degree) with VGH.

Thanks for any thoughts and assistance.


PS / More Detail:
Symptom
Half of screen has good video. Other half (left as viewed from front, right from back) has grainy texture. Side with grainy texture has a VGH/VGL voltage issue. Instead of +30/-12V as on “good” side, the bad side is ~+/-1.xx volts for VGH/VGL.

Narrowing it down
Trying to identify the load which causes VGH/L to pull down, the interconnect cable between the two right-side driver boards was disconnected, leaving the far-right driver board connected to the panel (since the 6 COF cables can’t be removed) .
Some resistances of note:

Resistance Checks
XLL (far left driver board) XRR (far right driver board):
VGH to Ground 787 k ohms 400 k ohms
VGL_G to Ground 760 k ohms 4.0 M ohms

CK1_I, 2_I, 3_I ,4_I to VGH 3.8-4.0 M Ohms 2.2-4.0 M ohms

CK5 to VGH 4.0 M Ohms 12.5 k ohms

CK6 to VGH 4.1 M Ohms 21 ohms

STV1 to VGH 3.7 M Ohms 8.0 M Ohms

RESET1 to VH 3.4 M Ohms 1.5 M Ohms

So, I see a problem with the low resistance between VGH & CK6 mostly.

[budwich]

Re: Sony XBR65x930D - left half screen is grainy

take a look at the tabs on the right side of the panel... check them for heating and also feel if there is any difference.

[budwich]

Re: Sony XBR65x930D - left half screen is grainy

One more thing.... back to your test of "give it the finger"... :-) This "test" was done on the connected edge board to cause a "good picture" on the half of the half. That indicates a problem on the center right edge board as this "method" is not required to get a good picture IF the edge board is OK. The means that you should also do similar checks that you did for the outer board to see what differences there might be.

[misterhaus]

Re: Sony XBR65x930D - left half screen is grainy

I have tried to disassemble the panel to get to the right side tabs. It's a very thin panel with a pressed on metal trim piece (not screws) and I can't seem to get it off without risking damage to the screen.

See here:


Also, I ordered the DE-5000 LCR (/ESR) meter which is supposed to arrive Saturday. Maybe it helps identify the bad capacitor that causes the finger-related issue on XRL driver board.

[budwich]

Re: Sony XBR65x930D - left half screen is grainy

You are going to find that a lot of the SMD components on the edge boards are in parallel and that perhaps one is not functioning properly. Usually in the worse case, people find shorted ones but in your case, I am thinking you might have a leaky one (can't hold its charge very well.

Indeed be very careful with the bezel work. Depending on how it is put on, some care be very tough to deal with. Having said that, it is still quite possible that you have a problem with the side drivers which is causing an issue with the outer edge board in terms of what you have seen.

[misterhaus]

Re: Sony XBR65x930D - left half screen is grainy

Another photo after partial separation of LCD PANEL from backlight (middle items in photo).

I don't see any side tabs.







Wonder if anyone else has pulled apart a Sony 2016 (or newer?) panel to show what it looks like inside.

[budwich]

Re: Sony XBR65x930D - left half screen is grainy

you are looking on the wrong side... you have to look from the front. that's why you need the front bezel off. further there are no boards just tabs / chip drivers.

[misterhaus]

Re: Sony XBR65x930D - left half screen is grainy

The trim at bottom edge is already removed.

This panel doesn't have a front bezel.

Maybe this photo shows that corner better? The ribbon cable goes into epoxy like potting on back of glass.


Here's a photo of the V650DK6 panel from PanelLook, showing the relatively clean sides of the panel (no tabs visible).

[budwich]

Re: Sony XBR65x930D - left half screen is grainy

ok... but look toward the middle of the side... the tabs are probably about half the width to the bottom ones. having said that, be careful because there could no side tabs... then there maybe another approach.

[misterhaus]

Re: Sony XBR65x930D - left half screen is grainy

Based on my added image above (PanelLook website image of this same V650DK6 panel), I don't think there are any visible side-tabs.

What is the other approach?

PS - I appreciate your continued attention to this issue!

[budwich]

Re: Sony XBR65x930D - left half screen is grainy

when there no are no tape, then there is potentially a means of "cutting off" the "in glass drivers" on the side.... it is referred to as "tape cut / cutoff".... but it usually appears in smaller two cable tcon to panel setups and is done at that at that connector.