LG 32LD750 bad chip or bad BGA?

[dominik0801]

I have a TV that I stated in the title.

The problem is really easy: when you turn on the TV, the picture is fine, but after a few minutes, it's full of bad, random colored pixels, horizontal lines and the picture is jumping/flickering..

There are 2 BGA chips (not counting the memory chips) on the board, one seems to be the main chip, while the other communicates between the screen with the main chip.
This later chip is called "XD LGE7378B-LF". It has a little heatsink on it.
When I freeze it with freezespray, the picture gets totally perfect, but after a while, it starts to flicker/jump around again.

I tried to put a heatsink with a fan on it, but it didn't help. I would try to reflow it, but I don't have a preheater, and I don't know if my hot air station would be enough.

What do you think, is it a bad chip? Maybe a bad solder joint?

[Diah]

Re: LG 32LD750 bad chip or bad BGA?

would be good if you upload here focused photo on the Main boards and how the screen look with this noise-

freezing get better.. could be caps filter near by the chip are effected not the chip self.

always with LG we start to reset it with IN_STOP to avoid any wrong judgment of bad firmware.

[dominik0801]

Re: LG 32LD750 bad chip or bad BGA?

Unfortunately I don't have any kind of remote for this TV. So I guess the IN STOP is not really possible without it.

I upload some pictures of the board, and a video of the problem.

Video: link

On the pictures you can see the whole board, the chip area, and the back side of the board (chip area too).

I tested freezing the backside filter caps, but that didn't help.

[Diah]

Re: LG 32LD750 bad chip or bad BGA?

IN_STOP can be send via android apk with mobile had IR sender.. or DIY wave. or Service remote for LG.. TV RC cant send this command.
if the LVDS are clean. doing reset IN_STOP a must before any HW inspection.

[vinceroger69]

Re: LG 32LD750 bad chip or bad BGA?

IN_STOP can be send via android apk with mobile had IR sender.. or DIY wave. or Service remote for LG.. TV RC cant send this command.
if the LVDS are clean. doing reset IN_STOP a must before any HW inspection.

lg in-stop apk

[dominik0801]

Re: LG 32LD750 bad chip or bad BGA?

I downloaded your files, and built an IR blaster real fast. The IN_START works, however, the IN_STOP won't.

EDIT: also, i dont know if this is important.. but whenever I turn the TV on, the LG logo comes in. That logo is shown PERFECTLY and there are no glitches. However, as soon as the logo goes away, the problem starts.

[dominik0801]

Re: LG 32LD750 bad chip or bad BGA?

Well, guys, I am really impatient so I simply took it apart, and reflowed the chip I was talking about.

That didn't help anything.

I didn't wanna stop there, so I took it out again, and reflowed the other only BGA chip (which is the main processor).

After this, the TV got a lot faster, it's not choppy in the games anymore either. And guess what, the problem went away..

now the only question is: how long will it last?

[nomoresonys]

Re: LG 32LD750 bad chip or bad BGA?

Maybe try a fan solution to try to keep the bga from overheating.