Sony KDL-40W3000 no picture (+ possibly no sound)

[xen0n54]

Hello all,

This is my first time diagnosing/repairing a TV and I'm looking for some guidance.

Backlight turns on
no picture

The sound I couldn't diagnose with certainty, my mother said that when it just broke there was still sound without picture. When I tried connecting a game console to the inputs and cycling through them blind I couldn't get a sound. Was this a problem with my technique, or can I assume that sound doesn't work?

Am I right in assuming than no sound + no picture = bad main board
and no picture + yes sound = T-con board?

I have yet to take the cover off and inspect the inside.

Before full death, the picture had a wide horizontal discolored stripe of pixels (lower brightness), but this was a long time before the final failure so I don't know if this is a separate issue or not.

[nomoresonys]

Re: Sony KDL-40W3000 no picture (+ possibly no sound)

Try test #3 below, try to do it just as instructed.

[nomoresonys]

Re: Sony KDL-40W3000 no picture (+ possibly no sound)

Sometimes you just need a firmware update but I did not see it on the U.S. site or the U.K. site.

[ngth82]

Re: Sony KDL-40W3000 no picture (+ possibly no sound)

Can you post clear pictures of the boards for this TV? power supply, main board and T-CON?

Do you have a multi-meter? Can you measure the voltage on either side of the T-Con fuse with respect to the chassis ground?

[xen0n54]

Re: Sony KDL-40W3000 no picture (+ possibly no sound)

I've checked all the pin voltages coming out of the power supply like you asked.
Here are the results

		STBY	ON

12V		12.32	12.30
12V		12.32	12.30
GND		0	0
GND		0	0
GND		0	0
6V		6.39	6.28

12V		12.32	12.30
12V		12.32	12.30
12V		12.32	12.30
12V		12.32	12.30
GND		0	0
GND		0	0
GND		0	0
NC		0	0
6V		6.39	6.28
6V		6.39	6.28
GND		0	0
GND		0	0
GND		0	0

12V		12.32	12.30
12V		12.32	12.30
GND		0	0
GND		0	0
AUDIO_GND	0	0
AUDIO_GND	0	0
AUDIO_VCC	13.67	13.80
AUDIO_VCC	13.67	13.80

NC		0	0
NC		0	0
BALANCER_ERR	0	0
12V		12.32	12.33
GND		0	0
INV_ERR		0.05	3.20
BACK_LIGHT	0	3.14
DIMMER		0.67	2.23
GND		0	0

BALANCER_ERR	0	0
INV_ERR		0.05	3.2
BACK_LIGHT	0	3.25
DIMMER		0.67	2.23
GND		0	0
AC_RLY		4.89	4.88
PFC_DET		2.97	2.97
PS_ERR		0	0
STBY_5V		4.93	4.93
GND		0	0
GND		0	0
NC		0	0

[xen0n54]

Re: Sony KDL-40W3000 no picture (+ possibly no sound)








my phone camera isn't great and the lighting conditions are bad as well, so please tell me if you need more detail in a certain area.

[budwich]

Re: Sony KDL-40W3000 no picture (+ possibly no sound)

From your very nice list of measurements, it appears that you have an inverter err for driving you backlights. Hopefully, you can do some looks around that area and maybe spot an issue. Otherwise, small voltage (and maybe some resistance) checks might be useful.

[xen0n54]

Re: Sony KDL-40W3000 no picture (+ possibly no sound)

Can there be a problem with the inverter if the backlight is working? I get a glow when the TV is turned on.
Visually I don't see anything obvious.





What measurements could I make?

[nomoresonys]

Re: Sony KDL-40W3000 no picture (+ possibly no sound)

Some there for about 20 Euros: https://www.benl.ebay.be/sch/i.html?...1181A&_sacat=0

[xen0n54]

Re: Sony KDL-40W3000 no picture (+ possibly no sound)



This is the image when the right T-con connector is disconnected.
Is it definitely the inverter board that needs to be replaced?

[nomoresonys]

Re: Sony KDL-40W3000 no picture (+ possibly no sound)

Can't say for sure but as mentioned it looks like you have a inverter error signal on your test.

[ngth82]

Re: Sony KDL-40W3000 no picture (+ possibly no sound)

Hold on... the last post shows the text on the screen --- you seem to be getting video on the screen.

Is this behavior different than before? In post #1, you said you got no video at all.

[xen0n54]

Re: Sony KDL-40W3000 no picture (+ possibly no sound)

Indeed, this is new behavior. After disconnecting the right T-con connector (viewed from the backside) half the picture is fine, the other is white (disconnected).
I now also have sound enabled, the TV was set to "audio through receiver" and with the partial screen I could reset it to play through the TV speakers.

[budm]

Re: Sony KDL-40W3000 no picture (+ possibly no sound)

Hold on... the last post shows the text on the screen --- you seem to be getting video on the screen.

Is this behavior different than before? In post #1, you said you got no video at all.

1) +1
2) So you do have image on the screen when one cable between the tab bonding board and the T-CON board is NOT connected.
3) The boards shown in your post #8 are Balancer board, not Inverter board, the Inverter board is the one to the right of the main power supply board.
4) The inverter and backlights are fine otherwise you will not have any backlights.
5) I would check the caps and connection on the tab bonding board (the board between LCD panel and the T-CON board).

[xen0n54]

Re: Sony KDL-40W3000 no picture (+ possibly no sound)

Thank you for your replies!

Are there any guides to getting to the tab bonding board on my TV or similar models, it's not immediately obvious how I should disassemble further.

Inspection of the inverter board (correct one this time) again didn't reveal anything obvious, but the working picture and backlight would suggest that it is indeed working fine.

[ngth82]

Re: Sony KDL-40W3000 no picture (+ possibly no sound)

Quick notes:

1) Please attach photos and dont put them inline with the post.
2) As mentioned in post #14, your backlight inverter board is fine otherwise you would not get backlights.
3) What happens you swap LVDS cables on the TCON (have the other one disconnected -- opposite of what you showed in Post #10?)
4) The tab bonding board will require substantial disassembly for this unit. Basically start with by removing the front faceplate/bezel.

High voltages on the power boards can kill. Don't touch anything until the unit is discharged. Use a DMM to verify that the PFC caps are discharged... those are about 300-400 volts.

[xen0n54]

Re: Sony KDL-40W3000 no picture (+ possibly no sound)

Apologies for the bad photo etiquette.

My T-con board is glued pretty hard into place (board flexing when trying to remove) so I can't check what switching the LVDS cables does.
I will try to disassemble further tomorrow when I can use some heat to release the board and when I find some guides for disassembly.

I will keep you updated.

[ngth82]

Re: Sony KDL-40W3000 no picture (+ possibly no sound)

The T-CON likely has a thermal interface material/gap pad for thermal transfer on to the chassis. You don't need to remove it... yet. I was just asking if you can disconnect the "other" LVDS cable... does disconnecting the cable that controls the right hand side of the screen (and have the left hand side connected) make a difference?

[nomoresonys]

Re: Sony KDL-40W3000 no picture (+ possibly no sound)

Ok, thought the inverter was ok if it lit up the screen but didn't know if the engineers added something weird on it. lol.

[xen0n54]

Re: Sony KDL-40W3000 no picture (+ possibly no sound)

Sorry, I misunderstood what you requested. With the LVDS cables reversed (left side screen connected, right side screen disconnected) there is a full black screen.