Panasonic TX-L42E6B Has Backlight & Sound, no Picture

[Billsy]

Good evening all. I have picked up this set that was reported to be dead. When I powered it up, it worked perfectly for a couple of minutes. I then powered off/on and the picture is no mo. The backlight is working fine as is the sound.

Test pads on Tcon are all very low until I pull the left side ribbon cable, the voltages then come up and the right side of the screen is working.

Can't see any shorts on the left side LCD driver board (if that's what you call the long thin pcb that hangs from the LCD?) There isn't much to check on those boards, looks like just sm caps and maybe diodes.

Bad panel? Anything else I can check before I strip it? Cut left side COF tabs perhaps?

I'll load pictures if required.

Many thanks

[nomoresonys]

Re: Panasonic TX-L42E6B Has Backlight & Sound, no Picture

Do the same with the right side, see if you get same result on that side, I don't pull any connectors while tv plugged in, with tv unplugged pull ribbon cable then plug in tv and check, less chance of shorting things out that way.

[Billsy]

Re: Panasonic TX-L42E6B Has Backlight & Sound, no Picture

Do the same with the right side, see if you get same result on that side, I don't pull any connectors while tv plugged in, with tv unplugged pull ribbon cable then plug in tv and check, less chance of shorting things out that way.

Yes I did try that. With the left ribbon in-place and right side out, there is no picture. I also never move anything while powered up!

Thanks

[nomoresonys]

Re: Panasonic TX-L42E6B Has Backlight & Sound, no Picture

Could be panel problem.

[nomoresonys]

Re: Panasonic TX-L42E6B Has Backlight & Sound, no Picture

.

[Andrew F. Ali]

Re: Panasonic TX-L42E6B Has Backlight & Sound, no Picture

Look for a shorted SMD cap on the left Panel Bd.

[nomoresonys]

Re: Panasonic TX-L42E6B Has Backlight & Sound, no Picture

Could try checking your capacitors on the tcon for shorts, diode mode.

[Billsy]

Re: Panasonic TX-L42E6B Has Backlight & Sound, no Picture

As a last resort I released the left ribbon while powered up and wiggled it about and I managed to find a position where it was happy, pushed the clamp down and picture is working fine. Question is will it last? I'm guessing the connection is worn? Should I put some tape on the back of the ribbon to give more clamping force?
Thanks

[Billsy]

Re: Panasonic TX-L42E6B Has Backlight & Sound, no Picture

I did give it a good clean!

[nomoresonys]

Re: Panasonic TX-L42E6B Has Backlight & Sound, no Picture

If its working, the cleaning and or reseating may have been all you needed.

[Billsy]

Re: Panasonic TX-L42E6B Has Backlight & Sound, no Picture

So before re-assembling the TV I tried a reboot and the picture was gone again. I was about to order a tcon board but I was sure the one in the set was ok so I cut off the left side tabs and it now works perfect.

Guys is there a long term "side" effect when removing these tabs? What are they for?

Thanks for your help