[SOLVED] Monitor turns off/on more frequently until dead. (Trying to diagnose, suspecting logic board)

Nibbzey

Prominent
Oct 3, 2019
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I'm trying to figure out if this is a logic board or PSU problem.

I have an AOC C27G1 that recently started turning itself off (even without connection), at first it was about a week between the shutoffs but got gradually worse until you could barely see the AOC logo when starting it up before it shut itself off. And now it won't turn on at all (no led light). I disassembled the screen and made a visual inspection of the PSU and the logic board and nothing seemed burned (i.e. capacitor).

The PSU seems fine as I plugged it in and measured the connection that goes from the PSU to the Logical board and got the 19V that it is supposed to supply. The capacitor also charged to a stable voltage.

Does anyone have any experience as to what might cause a monitor to gradually turn itself off and become more frequent? And/or anything that I could try/measure.

I'm suspecting that this is a logic board problem but that's just my intuition and not based on any "real knowledge", I'm currently thinking about baking the logic board. Why? I mean at this stage why not.
 

Lutfij

Titan
Moderator
Often times the issue can and will be with the logicboard since that's where everything takes place. The power source, due to your inspection, shows that there's nothing wrong there which would indicate a logic board that starts to behave erratically as it heats up or the longer it operates. You sure you scoured each square inch of the logic board, from it's power input to the video outputs? SMD's would also need inpseting.
 
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jay32267

Glorious
If the PSU is supplying what it is supposed to (got the 19V that it is supposed to supply ).
...and there are no other voltages or boards involved....I think it's probably a component on the control board that is failing or has failed.....and the failure mode was probably temperature related. I don' think baking it will help....but there's nothing to lose.
 
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Lutfij

Titan
Moderator
Often times the issue can and will be with the logicboard since that's where everything takes place. The power source, due to your inspection, shows that there's nothing wrong there which would indicate a logic board that starts to behave erratically as it heats up or the longer it operates. You sure you scoured each square inch of the logic board, from it's power input to the video outputs? SMD's would also need inpseting.
 
Reactions: Nibbzey

Nibbzey

Prominent
Oct 3, 2019
8
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510
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Often times the issue can and will be with the logicboard since that's where everything takes place. The power source, due to your inspection, shows that there's nothing wrong there which would indicate a logic board that starts to behave erratically as it heats up or the longer it operates. You sure you scoured each square inch of the logic board, from it's power input to the video outputs? SMD's would also need inpseting.
Could I assume the possibility of it being a single component that got overheated/damaged and then graduality worse when ON? Or is it normally more components that die? And oh no, I haven't checked the logic board at all, just the PSU. I'm not really good at troubleshooting components on PCBs like SMD's, I'm currently looking at motherboard diagnose videos trying to learn a bit.
 

Nibbzey

Prominent
Oct 3, 2019
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510
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If the PSU is supplying what it is supposed to (got the 19V that it is supposed to supply ).
...and there are no other voltages or boards involved....I think it's probably a component on the control board that is failing or has failed.....and the failure mode was probably temperature related. I don' think baking it will help....but there's nothing to lose.
I think your right, I'll hold off the baking for now and see if I can find and pinpoint the problem.
 

Nibbzey

Prominent
Oct 3, 2019
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510
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Update

I bought a second monitor of the same model and replaced the logic board and now it works. So in my case, the logic board failed. I'm going to buy a replacement logic board from eBay and replace it, meanwhile, I'll try and see if I can locate what exactly broke in the original logic board.
 

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