Samsung UN46D6500VF - no display, odd lines and double image on half of display

[viewfindr]

Hi there, I'm seeing some tips/advice on how to pinpoint what might be going on with my TV. This is a continued discussion from this thread, as users suggested I should start a new topic to discuss my problem. In summary:

Before I took the set apart, I started to see a double image come on after the set is powered on for a few minutes. (attachment #1).

I came across this YouTube video, which seemed to describe a very similar phenomenon from what I was seeing. (In summary, the video suggests unplugging one cable, and using a small clear piece of tape to cover various pins on the cable until the entire image comes back together).

Then, I took the set apart, and started messing with the left ribbon cable on the T-Con board to try and cajole the picture together.

However, it eventually started getting worse. After a while, I had a large white vertical band on the right side of the TV. Now, there is no picture at all when both ribbon connectors are connected, but the backlight still works. Audio comes through fine as well.

Per suggestion in the previous thread, I tried the set with one ribbon cable disconnected at a time. With only the right cable connected, half of the picture comes together, similar to before with the weird artifacts and double image (see attachment #2). With only the other cable connected, there is no picture. I've swapped both ribbon connectors around and can confirm both cables appear to be fine. These are the voltages that I obtained from the Tcon board:

With both cables connected:

VONE: 0.2V
VOFF: 0.1V
AVDD: 0V
VIN_12V: 12.7V

With only one cable connected, and picture showing:

VONE: 32.0V
VOFFE: -12.2V
AVDD: 17.1V

I've also attached a high res image of the Tcon board from shop jimmy (attachment #3).

I'm at a loss for what's going on - some have pointed towards a bad panel. However, according to the video I saw above, Samsung TVs do show black screens with half the TCon connected, so could it just be a bad tcon board?

Thanks in advance for any tips or suggestions.

[budm]

Re: Samsung UN46D6500VF - no display, odd lines and double image on half of display

VONE:
VOFF:
AVDD:

Check the resistance between those test points against GND when both cables from T-CON to panel is connected and when one is not connected at a time.

[viewfindr]

Re: Samsung UN46D6500VF - no display, odd lines and double image on half of display

VONE:
VOFF:
AVDD:

Check the resistance between those test points against GND when both cables from T-CON to panel is connected and when one is not connected at a time.

Here's what I got:

Both cables connected:
VONE: 41.8
VOFF: 7.4
AVDD: 6.3

Good (working) cable connected:
VONE: 41.6
VOFF: 7.4
AVDD: 7.5

Bad (black screen) cable connected:
VONE: 41.1
VOFF: 7.3
AVDD: 6.3

Seems like there's only a meaningful difference in the AVDD?

[budm]

Re: Samsung UN46D6500VF - no display, odd lines and double image on half of display

Are those reading in Ohms, K Ohms, or M Ohms?

[viewfindr]

Re: Samsung UN46D6500VF - no display, odd lines and double image on half of display

Are those reading in Ohms, K Ohms, or M Ohms?

K Ohms, I believe since my meter was set to "200k". Thanks for the help!

[budm]

Re: Samsung UN46D6500VF - no display, odd lines and double image on half of display

I am expect something <50 Ohms reading for typical failure due to bad caps on the tab bonding board.

[viewfindr]

Re: Samsung UN46D6500VF - no display, odd lines and double image on half of display

I am expect something <50 Ohms reading for typical failure due to bad caps on the tab bonding board.

To clarify, does that mean you think the panel is fine, and the issue is in the Tcon board?

[nomoresonys]

Re: Samsung UN46D6500VF - no display, odd lines and double image on half of display

No, the board between the tcon and the panel, test the little MLCC caps for lower than 50 ohms, meter set to ohms of course with tv UNPLUGGED from power.

[viewfindr]

Re: Samsung UN46D6500VF - no display, odd lines and double image on half of display

No, the board between the tcon and the panel, test the little MLCC caps for lower than 50 ohms, meter set to ohms of course with tv UNPLUGGED from power.

I just got down to that board, and realized that there are also test points for AVDD, VDD, HVDD, VCOM, etc. and a GND point. Testing the caps between each other (on each end of the MLCC cap) doesn't yield any readings with my meter set to 200. However, with the negative lead on the GND point, I get about 2 ohms on some of the caps. Seems like results are similar on both sides. Is this a good or bad sign?

[budm]

Re: Samsung UN46D6500VF - no display, odd lines and double image on half of display

May be show us good clear pictures of the tab bonding boards so we can see the caps, etc.

[viewfindr]

Re: Samsung UN46D6500VF - no display, odd lines and double image on half of display

May be show us good clear pictures of the tab bonding boards so we can see the caps, etc.

Attached below - let me know if these are clear enough to see.

In order from left to right, first 3 are the left board, second 3 are the right board for the 6 tabs in total.

[budwich]

Re: Samsung UN46D6500VF - no display, odd lines and double image on half of display

I just got down to that board, and realized that there are also test points for AVDD, VDD, HVDD, VCOM, etc. and a GND point. Testing the caps between each other (on each end of the MLCC cap) doesn't yield any readings with my meter set to 200. However, with the negative lead on the GND point, I get about 2 ohms on some of the caps. Seems like results are similar on both sides. Is this a good or bad sign?

do similar voltage checks across each side (as you kind of did during the first post) to compare sides. Do this with one cable connected.... checking the difference between the two side. It is likely that the side that provides no picture / nothing when the tcon to panel cable is connected also sees little / no voltages on those test points.

[viewfindr]

Re: Samsung UN46D6500VF - no display, odd lines and double image on half of display

do similar voltage checks across each side (as you kind of did during the first post) to compare sides. Do this with one cable connected.... checking the difference between the two side. It is likely that the side that provides no picture / nothing when the tcon to panel cable is connected also sees little / no voltages on those test points.

Some interesting findings today: with only the bad side plugged in and power applied, no voltages are present (0V across the board, screen completely dim). However, I found out that if I power the TV on with the "good" side connected and then switch the connection over to the "bad" side, then the vertical white strip comes back, and I get a partial image on the other half of the screen. The voltages then make more sense as well, and are actually quite similar:

"Good" side:
VDD 1.7V
AVDD: 17.1V
HAVDD: 8.5V
SVCOM: 7.6V

"Bad" side, after cable switched:
VDD: 1.7V
AVDD: 17.0V
HAVDD: 8.6V
SVCOM: 6.9V

What could this mean?

[viewfindr]

Re: Samsung UN46D6500VF - no display, odd lines and double image on half of display

Bump for suggestions - I find it curious that the panel partially works when the cables are switched around, but not when connected directly. Is this an indication of a tcon, mainboard, or power issue?

[Moreno83]

Re: Samsung UN46D6500VF - no display, odd lines and double image on half of display

This is as BUDM says a problem in the t-con or panel. The D5000 and 6000 series are known for bad panels.
Let's wait for BUDM to respond , im curious!

[nomoresonys]

Re: Samsung UN46D6500VF - no display, odd lines and double image on half of display

"Testing the caps between each other (on each end of the MLCC cap) doesn't yield any readings with my meter set to 200." this seems wrong, is your meter working correctly? try measuring some of the little MLCC caps on the tcon, probe on each end of cap, see what you get.

[viewfindr]

Re: Samsung UN46D6500VF - no display, odd lines and double image on half of display

"Testing the caps between each other (on each end of the MLCC cap) doesn't yield any readings with my meter set to 200." this seems wrong, is your meter working correctly? try measuring some of the little MLCC caps on the tcon, probe on each end of cap, see what you get.

Just tried on the tcon, and couldn't get much of a reading either. Only one of the larger caps (labeled B1) came up with a reading of 0.2 ohms. None of the smaller units caused any movement. I tried two meters, but neither of them are very good, so maybe that's the issue?

[nomoresonys]

Re: Samsung UN46D6500VF - no display, odd lines and double image on half of display

Just tested some with a 5 dollar Harbor Freight meter, they read over 120, sometimes you need to re-apply probes to get a reading to make sure you have good contact, you need to look quick because it will give the reading then go back to 1 in about a second til you re-apply the probe.

[dick_barton]

Re: Samsung UN46D6500VF - no display, odd lines and double image on half of display

Only one of the larger caps (labeled B1) came up with a reading of 0.2 ohms.

None of the capacitors should read 0.2 ohms. I would lift it off the board and check again.

[budm]

Re: Samsung UN46D6500VF - no display, odd lines and double image on half of display

B1 is not capacitor, it looks to be inductor.
BTW, back to your reaindgs in post #1:
With both cables connected:

VONE: 0.2V
VOFF: 0.1V
AVDD: 0V
VIN_12V: 12.7V

With only one cable connected, and picture showing:

VONE: 32.0V
VOFFE: -12.2V
AVDD: 17.1V

Those readings go down to 0V when the bad side cable is connected, that bad side is loading down the those switching power supply outputs. Are you 100% sure that the resistance readings of the caps on the tab bonding boards are done correctly.