Light color 'ring' around screen?

Hi there,

Just recently acquired and assembled my uConsole (CM4+Wifi).
I’ve been setting it up, and I notice a light ‘ring’ of discoloration on the screen. It’s very visible with my choice of background color… but it’s visible on any background that’s darker than full white, including the bootup/shutdown tty.
Does anyone else have this? Was this an assembly error on my part? Do I have a dud panel?

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That looks like a defect with the adhesive on the polarizer layer on the display. Message Alex for a replacement screen?

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It has more to do with the CM4 getting too hot. Make sure the thermal pad is sitting on top of the CPU and nothing is resting against the back of your uConsole while you are using it. I had this happen, I watched it go away after I picked it up and the back cooled off.

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watch a few videos or a movie or two and see if it fades away.
I had a similar problem after I messed with LCD timing settings on my devterm. thank goodness it wasn’t permanent!

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Hi all, thank you for your replies. While it was there consistently at first, it does indeed seem to have dissipated with time and its intensity does seem correlated to temperature. I have been careful to avoid things resting against the back of the device while it is in operation and the ring has disappeared entirely (at least as far as I can perceive) and I have not seen it return.

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I’ve got same issue, seems it comes everytime if I leave the device idol until it go into sleep mode, and when wake-up the device the problem comes.

But it’s also looks cool, don’t you think so? like an antique device from last century

I have noticed this tends to happen when my uconsole is plugged in / charging for a long time, but not on every chargers.

I guess chargers that delivers less amperes are less likely to cause heat, and this weird artifact on the screen.

I think is some type of image retention, not heat related.

As an experiment I installed xscreensaver, and set the penrose one (because it’s cool), and tested charging, and compiling things.

The device gets hot, but no ring around the screen so far.

I am not so sure about that.

I configured dpms so my screen shuts off after 5min of keyboard / trackball inactivity and the first time I noticed the ring was when waking the screen up after a very long SSH session to the uconsole from my main computer (installed and compiled lots of stuff for about 5-6 hours). The device was plugged in the whole time.

The second time I noticed it, the uconsole was on but idle in a closed case for like 2-3 hours. When I opened the case, the device was quite hot from staying in there without ventilation and the instant I woke up the screen the pattern was already there.

Definitely heat related for me.

Moreover, if it was image retention, I guess the pattern would look like something that was printed on screen ? But it seems that we all experience the brightness “ring”.

I agree that is not normal image retention (that is why I said some type of :stuck_out_tongue: ), but the funny thing is that I had also set the screen to shut off, and it was shut off the 2 times that I had experience the ring, but after I set xscreensaver I haven’t seen the ring again, Also, weirdly, the first time I saw the ring, my uconsole was idle, non my desk, with the screen off, resting on the wired support so the back was in the air.

But yeah, it looks like the ring is pretty common.

Yeah, just yesterday I got it after letting my uconsole plugged, but it was clearly not hot (around 40°C).

So also not so sure about heat anymore :smiley:

Maybe the amount of current received ?! Maybe it’s just some kind of black magic.

I did a new experiment.

  1. Setting the screen to shut off using dpms after 1 minute. Then long ssh session compiling and doing stuff => ring shows after I wake up the screen.

  2. Manually shut off the screen using xrandr --output DSI-1 --off, then long ssh session compiling and doing stuff => no ring.

So my theory (that may be way off), is that dpms is turning off the backlight, but the screen is still showing something (probably some kind of color gradient that creates the ring).

What image do you think would cause burn-in to appear like this?

This, to me, looks like materials in the screen straining away from the nearest edge, which is why you see less of it around the corners.