Re: •• samsung * ku * range troubleshooting information ••
@CuriousJohn - did you ever figure out this issue?
I've got a UN65KU630D that is similar in that the LED backlights cycle on and off on about 7 second cycle. Backlights stay on constantly if I disconnect the cable between power supply and main board.
If I disconnect a single TCON cable (at main board), then the tv stays off when I plug in power. When I press power button I hear two tones and then the same 7-second backlight cycle.
If I connect both TCON cables, then...
misterhaus
Member
Last Activity: 07-26-2023, 08:23 PM
Joined: 12-26-2019
Location: Pleasanton CA
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Re: Sony XBR65x930D - left half screen is grainy
Yes, those boards (labeled 16STW-Board) are on both sides.
I'm pretty sure those boards are LED Backlight-related. This eBay post is selling the backlight assembly along with the same board.
[url]https://www.ebay.co.uk/itm/LED-BACKLIGHT-STRIP-BAR-LEFT-L-FOR-SONY-KD-65XD9305-TV-WITH-16STW-BOARD-/273830463894[/url]Re: Sony XBR65x930D - left half scre...ost is sellingLeave a comment:
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Re: Sony XBR65x930D - left half screen is grainy
Um, should I have been looking at these?
I have been thinking they are backlight related.
[ATTACH]209434[/ATTACH]...Leave a comment:
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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!Leave a comment:
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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.
[ATTACH]209432[/ATTACH]
Here's a photo of the V650DK6 panel from PanelLook, showing the relatively clean sides of the panel (no tabs visible).
[ATTACH]209433[/ATTACH]Re: Sony XBR65x930D - left half screen is grainy
The trim at bottom edge is already removed.
...Leave a comment:
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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.
[ATTACH]209428[/ATTACH]
[ATTACH]209429[/ATTACH]
[ATTACH]209430[/ATTACH]
Wonder if anyone else has pulled apart a Sony 2016 (or newer?) panel to show what it looks like inside.Re: Sony XBR65x930D - left half screen is grainy
Another photo after partial separation of LCD PANEL from backlight (middle items in photo).
...Last edited by misterhaus; 03-26-2020, 03:01 PM.Leave a comment:
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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:
[ATTACH]209411[/ATTACH]
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.Re: Sony XBR65x930D - left half screen is grainy
I have tried...Leave a comment:
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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.)
...Leave a comment:
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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...Last edited by misterhaus; 03-21-2020, 11:36 PM.Leave a comment:
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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):
[url]https://cdn.badcaps-static.com/pdfs/8d9e3431b36112a84fa49b1a3342642b.pdf[/url]
I've got my oscilloscope out and am checking various things. This is my first driver board diagnostic - so I'm not clear on...Leave a comment:
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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....Last edited by misterhaus; 03-21-2020, 12:59 PM.Leave a comment:
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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.Leave a comment:
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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.Leave a comment:
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Re: Sony XBR65x930D - left half screen is grainy
Some resistance measurements on the left and right outer most edge boards (while disconnected from interconnect to inner edge boards. My thought was to look for lower resistance on right board with “problem”.
Value Left / Right
VGH 787k / 400k
VGL_AA 4.1M / 3.9M
VGL_G 760k / 4.0M
VDD 23k / 23k
VDDA 2.3M / 2.5M
VDDAM 3.2M / 2.4M
Admittedly, a few of the Megohm values were changing (as caps charged?) so I approximated.Leave a comment:
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Re: Sony XBR65x930D - left half screen is grainy
With the interconnect between the two right edge boards disconnected, I get the image attached.
The right side of screen is split in two patterns. Far right is evenly bright white.
Other half of right side is vertical strips of very light grey, with varying darkness from center to middle right....Leave a comment:
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Re: Sony XBR65x930D - left half screen is grainy
@jjanssen7: In my table of voltages above, the third column is with the right most board disconnected. The voltages go to “normal” which supports the theory something is wrong on that board, or the panel section that connects to that board (I’m trying not to accept that possibility).
I’m not sure how to approach checking that board - should I check resistance between the VGH and VGL test points to ground on the same board?Leave a comment:
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Re: Sony XBR65x930D - left half screen is grainy
Yes, exactly. There are two edge boards for "left" and two for "right" half of screen.
The right two are connected with a ribbon cable between them. Same with the left.
Image attached....Leave a comment:
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Re: Sony XBR65x930D - left half screen is grainy
Well, a few updates, no success yet.
First, I had ordered a replacement TCON board before posting this thread, and as predicted, it didn't change anything. They key being that when the right-most of 4 LCD edge boards are disconnected (remove ribbon connecting two right-most edge boards), the TCON voltages are normal on both sides.
I've done a bunch of checking capacitors on the edge boards, found nothing less than kilohms - most are megohms. There are a couple of ICs on the edge boards. Googling didn't...Leave a comment:
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Re: Sony XBR65x930D - left half screen is grainy
Thanks - that's what I'll do!Leave a comment:
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Re: Sony XBR65x930D - left half screen is grainy
Understood. I had pulled the edge trip off before to visually inspect the LCD ribbon cables connected to the edge boards, and didn't see anything visual. I may have a line on another TV just like this one - although if it's one of the edge boards next to the display, I don't think I can swap those (if they're attached to the LCD screen).
Are there any common failure components on those screen-connected boards?Leave a comment:
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