BenQ G2420HDBL weird white patterns

[ntoskrnl]

I have a BenQ G2420HDBL from 2010 that exhibits white, flickering, static-like image distortion (see photo). It is accompanied by a slight buzzing sound from the upper corner, either from the TCON board or the panel itself. The ~10Hz rate of buzzing seems to match the flickering. It also appears that the physical orientation of the monitor affects the pattern -- it seems to get a little better when the monitor is laid on its back.

The distortion happens even when no video input is connected. Other than this distortion, the monitor works fine.

I tried the panel and TCON from the broken monitor with the rest of the hardware (power supply and mainboard) from an identical but working monitor, and the problem remained. So the problem must be in either of those components.

When I disconnect the LVDS ribbon cable between the mainboard and the TCON, the screen is all white (as expected) with no distortion or buzzing.

There are no obvious visual issues with the TCON board (such as burn marks).

The TCON board seems to be permanently attached to the panel on this monitor with brown ribbon cables, so I'm not sure if I can replace anything. Got any suggestions what to check, or should I just junk it?

[selldoor]

Re: BenQ G2420HDBL weird white patterns

Good clear picture sof the Panel board might help and also one of the whole
board showing the ribbons. If you gently press on the ribbon nearest the problem
does it change at all?

[ntoskrnl]

Re: BenQ G2420HDBL weird white patterns

I removed some more tape so I could get better access to the TCON and the brown ribbons. I wiggled all of them around but there's no effect on the picture.

I now also think the buzzing sound is coming from the panel and not the TCON. There's a coil on the TCON which I tried pressing on with no effect. What could make such a noise inside the panel?

This one has LED backlights so it's not that either.

Sadly the only camera I have here is a friend's phone, so I'm not sure I can get clear pictures.

[selldoor]

Re: BenQ G2420HDBL weird white patterns

could be a tab bond where the brown ribbon attaches to the panel or possibly a led lamp
going out.

[ntoskrnl]

Re: BenQ G2420HDBL weird white patterns

I'm going to junk it since the problem is in the panel.

[tom66]

Re: BenQ G2420HDBL weird white patterns

Did you check for 5V/12V at the panel, is it steady? I have had this issue with low PSU outputs.

[ntoskrnl]

Re: BenQ G2420HDBL weird white patterns

I checked the panel with a known working power supply and mainboard like I said.

[selldoor]

Re: BenQ G2420HDBL weird white patterns

If you are going to junk it you may as well open the panel up and see if it is the leds or try and give it away on freecycle - someone may be able to use it?