Vestel 50 inch LED backlight, Sound, No picture.

[Ronan Wood]

Hello, I was recently given this tv by a family member.

model LUXOR LUX0150004 01
screen VES500UNDA 2D N03
Power 17IPS71
MB 17MB95
TCON T420HVN06.3 CTRL BD 42T34-C03


I have only carried out basic repairs to tvs in the past. Changing capacitors and LEDs ect. And have not yet come across this fault.

The backlights light, the tv responds to the remote indicating the software is ok but no picture. Always a blank screen.

As per the advice on other similar threads I removed and cleaned the contacts on the LVDS cable to no avail. I have also attempted to remove each of the 2 ribbon cables coming out of the TCON board to still have the same blank screen.

I am thinking I have a panel fault or a faulty TCON board. I have no idea how to identify the small components on there or how to test / verify this.

Please see attached pictures of the TCON board.

Any advice is greatly appreciated, Thanks.

[budm]

Re: Vestel 50 inch LED backlight, Sound, No picture.

Did you verify that you do have 12v dc at both ends of the SMD fuse of the T-CON board with ref to chassis gnd?
If you do have 12V DC, then what do see on the screen if you have only one cable between the T-CON and the LCD panel connected one at at time?

[Ronan Wood]

Re: Vestel 50 inch LED backlight, Sound, No picture.

Is there any way for you to point the fuse out to me ? Does it have the letters F101 above it ? cheers.

[dick_barton]

Re: Vestel 50 inch LED backlight, Sound, No picture.

You can check you have 12 volts at the test points V12INI and V12

[Ronan Wood]

Re: Vestel 50 inch LED backlight, Sound, No picture.

Yes 12 volts at v12IN1 and V12

If I unplug each of the ribbon cables there is no change to the blank screen

[dick_barton]

Re: Vestel 50 inch LED backlight, Sound, No picture.

So you do have 12V supply to Tcon and fuse is OK.
Do you have sound or any indication that it responds to your remote control?

Also, did you flip up the black bar on the Tcon connector to remove / insert the ribbon cables. If you did not then the ends of the ribbon cables may be damaged.

[Ronan Wood]

Re: Vestel 50 inch LED backlight, Sound, No picture.

Yes I do have sound and it does respond to the remote and auto standby so the software must be ok. The backlight is also on.

The black bar was flipped and ribbon connectors are in perfect condition. I am very careful.

I tried only having one ribbon connector in at a time as suggested above. This did not make any difference to the blank screen.

Yes 12 volts at the test points you suggested

[budwich]

Re: Vestel 50 inch LED backlight, Sound, No picture.

Normally, when one tcon to panel cable is disconnected, that "half" of the screen goes a "nice clean white" while the other side shows some form of picture. Please recheck this test. If necessary, post a picture.

[Ronan Wood]

Re: Vestel 50 inch LED backlight, Sound, No picture.

I have disconnected each panel to TCON cable and trust me the screen does not change at all. Only backlight showing

[dick_barton]

Re: Vestel 50 inch LED backlight, Sound, No picture.

The Tcon has a number of test points where you can take a reading with your meter.

VGH by C704
VGL by C702
VSS by R202
AVDD by L204
AGIN by C113

Perhaps someone could interpret the results as to whether or not they look normal for the tcon.

[Ronan Wood]

Re: Vestel 50 inch LED backlight, Sound, No picture.

VGH 0.18v
VGL 0.16V
VSS 0.02V
AVDD 0.34V
AGIN 0.00V

The above voltages were taken with the tcon connected to the pannel

Below with the pannel disconnected.

VGH 1.25
VGL 0.05
VSS 0.00
AVDD 1.34
AGIN 0.00

[Diah]

Re: Vestel 50 inch LED backlight, Sound, No picture.

i faced before 6 years or so same issue with TOSHIIBA 3d set which its was also from Vestel. i went direct to replace the TCON and the picture come straight clear

[dick_barton]

Re: Vestel 50 inch LED backlight, Sound, No picture.

Those voltage are really low and would be immediately suspecting the Tcon is at fault.
These are a typical Tcon voltage given by another member but obviously for his Tcon however the voltages I would expect to be within the range shown.

T-con voltages (typical)
1. Vin (Vcc): 12Vdc or 5Vdc
2. Vlogic,LCM, Vddd,VCC): 3.3Vdc
3. Vda (Vs, Vsource,VDD, Vdda,Avdd): 14Vdc~20Vdc
4. Vgh (Vgon,VGHR, Von, Vddg): 20Vdc~30Vdc
5. Vgl (Vgoff,VST,VGHF,VGHEVEN, Voff,Veeg): -5Vdc~-7Vdc
6. HVDD about 8v
7. DVDD,VDDC 3.3v, 1.2v
8. VCOM about 5~10vdc (about half of Avdd)

[Ronan Wood]

Re: Vestel 50 inch LED backlight, Sound, No picture.

Thank you very much for your time helping me with this.

I will replace the TCON and let you know if it is successful. Luckily enough these are only about a fiver on ebay.

Im glad there are people around willing to donate time and knowledge to keep these things out of landfill.

[dick_barton]

Re: Vestel 50 inch LED backlight, Sound, No picture.

Good luck.

[sordids999]

Re: Vestel 50 inch LED backlight, Sound, No picture.

Any update on this issue ?

[sordids999]

Re: Vestel 50 inch LED backlight, Sound, No picture.

Exactly the same fault
Backlight but no image on the screen,even if I disconnect the tcon ribbons one at a time it makes no difference what's so ever

[nomoresonys]

Re: Vestel 50 inch LED backlight, Sound, No picture.

If your getting the same low voltages at the test points, it's probably the tcon at fault.

[dick_barton]

Re: Vestel 50 inch LED backlight, Sound, No picture.

If you disconnect the tcon ribbons from the panel strip with the set powered off and then power up again do the tcon test voltages change?

[sordids999]

Re: Vestel 50 inch LED backlight, Sound, No picture.

Tcon ribbon connected
VGH 0.10V
VGL 0.00V
VSS 0.10V
AVDD 0.27V
AGIN 0.00

Tcon ribbon disconnected

VGH 1.21V
VGL 0.05V
VSS 0.00V
AVDD 1.31V
AGIN 0.00V
Any reason why theres nothing on the screen when you disconnect one ribbon at a time?
Normally you get a white screen each side

Thanks