LG Monitor [22MP55HQ] fading out into green&black and glitching out

StereoBucket · October 1, 2022

Hi, hope it's alright to ask for electronics help.

So I got an LG 22MP55HQ monitor. Issue is the screen fades into green and black in and out. Can be seen on the video.

I took it apart and couldn't see much other than ever so slightly bulged cap, and I figured I'd try replacing the 2 electrolitics on the board

First time it didn't work, it was slightly better but still had a bit of green near the bottom, so I ordered new caps and tried again, figuring I overexposed them to heat. This time it appeared to work for about 10 minutes without issue but it suddenly started doing the green fade. It gets progressively worse as the monitor is running. Starts off as few rows at the bottom fading out to more than half the screen a few minutes later with the effect being more pronounced (faded sections sometimes freeze and don't update).

Anyone have any suggestions on what I should try next? Is it worth trying?

Thanks in advance.

Budget DIY · October 1, 2022

I feel like you've gone WAY past what normal (boring) people would do. I assume you've tryed the monitor with some other device, to make sure it wasn't your PC/GPU? If so, I'd imagine most of us would scrap it at this point.

StereoBucket · October 1, 2022

4 minutes ago, Jahee said:

I feel like you've gone WAY past what normal (boring) people would do. I assume you've tryed the monitor with some other device, to make sure it wasn't your PC/GPU? If so, I'd imagine most of us would scrap it at this point.

I got a few monitors and devices, they all work fine except this one. This happens even when it's not plugged into anything, no signal prompt glitches too.

StereoBucket · January 23

Update: So I was just about to give up on this display, since the board itself was not an issue (verified by using a new board), and I was taking the monitor apart to throw it away, but decided to just poke around a little in case it was a loose connection somewhere or a broken cable that I missed.

I noticed that one spot on the thin wide pcb (that runs along the entire bottom) that is glued to the back, would cause the issue to go away when touched, but only by a finger, not plastic. So some sort of resistance or capacitance change fixes it.

I couldn't pin point which part was being affected exactly, and nothing too unusual showed up when measuring, so before putting it away to take a look later I sprayed the rough area with isopropyl alcohol to clean it off from all the finger grease I introduced... and now it's not glitching at all. It's been on for about an hour and, no glitchiness... Odd issue. Maybe moisture mixed with some residue? Or a tiny bug took a tiny poop... who knows.

But yeah, I just wanted to drop this update in case it ever helps someone. The rough affected area was this, right under the RT6807A chip.

I am still not 100% sure it's fixed, I don't want to entirely get my hopes up, keeping it on until it glitches again, and if it does, the cause it somewhere around here, or related to this spot. Otherwise, if it doesn't, I've got my monitor back and can set myself up with a triple monitor setup.