LD-4655VX - Audio, Backlight, but no Video

[skew]

The set I have lost video but audio kept working. I had the frayed ribbon cable problem that so many others have and repaired them, giving me two sides of bright LEDs working. But I still have no picture. I found a couple posts elsewhere that simply said "LCD bad". Maybe that's it, but I wanted to ask in a more knowledgeable forum before giving up.

If anyone has some suggestions on areas I can look at next, I'd appreciate hearing from you.

Thanks.
- Skew

[budm]

Re: LD-4655VX - Audio, Backlight, but no Video

If you have backlights but no pictures, then check the cable between the main board and the LCD panel, also check the SMD fuse on the T-CON board, also check the DC voltage on both ends of the fuse with ref to the chassis.

[skew]

Re: LD-4655VX - Audio, Backlight, but no Video

Thanks for the reply. I did see the troubleshooting guide you listed before posting, but I'm an amateur at best and was hoping for more 4655VX-specific insights. That said, I will be trying to cross-reference the guide information with my TV. The cable ohm'd-out ok. It'd be great to find a fuse, but I haven't seen one so far.

[tom66]

Re: LD-4655VX - Audio, Backlight, but no Video

Pictures of the boards would help.

[skew]

Re: LD-4655VX - Audio, Backlight, but no Video

Sure... there are some here:

https://www.badcaps.net/forum/showth...ight=LD-4655VX

[tom66]

Re: LD-4655VX - Audio, Backlight, but no Video

Near the cable going to the screen on main board, multi coloured wires (LVDS) there is a device marked Q13. What is part # on this device and also what voltage do you get on each pin, with the black probe on the chassis and red probe on each pin, DC 20V range.

[skew]

Re: LD-4655VX - Audio, Backlight, but no Video

It's marked:

44356M
101156

All pins are 12 except pin 4, which is 0.11.

[tom66]

Re: LD-4655VX - Audio, Backlight, but no Video

OK, that confirms the panel is getting 12V. The problem is either the panel or the main board not sending signals to the panel. The second is rare when you have audio. Check the fuse on the panel board, if it's easily accessible.

[skew]

Re: LD-4655VX - Audio, Backlight, but no Video

If the panel board is the board on the other side of the LVDS cable, I don't see any fuse. It's a strip on one side of LCD, with a couple of ribbon cables connecting it to a strip on the other side (which makes it seem like a panel board to me). Is this a "it has to be there" situation? Maybe I'm missing it, maybe it's a microfuse and not obvious, or maybe I'm looking at the wrong board. It's the one at the top of this image:

https://www.badcaps.net/forum/attach...4&d=1349118015

which unfortunately is covered with a protective film, but maybe you can tell if I should be looking for another board.

Regards,
- skew

[tom66]

Re: LD-4655VX - Audio, Backlight, but no Video

Yes, that's the panel board. Replaces the t-con but not replaceable due to it being bonded to the LCD panel. Can you get a closer shot of the connector from the main board to it, on the panel board end?

[skew]

Re: LD-4655VX - Audio, Backlight, but no Video

Here's the whole strip...

[tom66]

Re: LD-4655VX - Audio, Backlight, but no Video

Do you see the white device with a "K" mark on it? That is your fuse. With the TV powered on, measure the voltage on both ends, red probe each end black probe on chassis, DC20V.

[skew]

Re: LD-4655VX - Audio, Backlight, but no Video

It's got 12V on both ends.

[tom66]

Re: LD-4655VX - Audio, Backlight, but no Video

I suspect the panel is bad then. Possibly the main board, but it does not seem like it.

[skew]

Re: LD-4655VX - Audio, Backlight, but no Video

I've read plenty of bad comments about the quality of this particular Westinghouse model, and seen some signs of bad design first hand, so any board going bad isn't surprising. Thanks for the help, I greatly appreciate it.

[ecking767]

Re: LD-4655VX - Audio, Backlight, but no Video

BEFORE you give up, looking at picture #1, those two flat cables going to the left and right side of the T-CON board, looking at the black line, are they inserted correctly? Maybe its the camera angle?

[skew]

Re: LD-4655VX - Audio, Backlight, but no Video

Good eye... but that was me, I didn't seat it straight when I checked it the first time. I fixed it just now, no change, and no change to the voltage coming in, so I don't think my slight angle made things worse.

[ecking767]

Re: LD-4655VX - Audio, Backlight, but no Video

Good eye... but that was me, I didn't seat it straight when I checked it the first time. I fixed it just now, no change, and no change to the voltage coming in, so I don't think my slight angle made things worse.

okay I have this TV on my work bench and I had to change the flat ribbon cable going to the LED stripe. have you confirm the two ribbon are connected right, CN1 to CN1, CN2 to CN2. its not a bad TV, I'm watching it now.

[tom66]

Re: LD-4655VX - Audio, Backlight, but no Video

They have a backlight, so it shouldn't matter.

[ecking767]

Re: LD-4655VX - Audio, Backlight, but no Video

They have a backlight, so it shouldn't matter.

no on the T-CON board