Try to repair monitor which restarts constantly every few seconds.

Thread Starter

Lightportal

Joined Oct 2, 2021
4
Trying to find issue. I have monitor which had overheating problem, was placed in front of the window and sun lights caused overheating to some components internaly after few months started malfunctioning. As a result it restarts constantly (blinking, screen goes black and shows image again) every 3 to 10 seconds. But after few hours of rest it work well for an hour on average.
I have checked power block it works good, also tried connecting other 19.5 V charger block, still the same problem. So it's definitely not power block issue.
Also tried placing two coolers behind monitor processing unit. After that monitor is realy cold, but still restarts constantly every 3 to 10 seconds. But before it starts reseting it work well at least two hours.
What components can cause the issue. Can it be damaged capacitors (relatively because it works until same point)? From which point I should start investigating the problem?
Ps. can't see any damiged capacitors or other signs of overheating.
 

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dl324

Joined Mar 30, 2015
15,113
Welcome to AAC!
Also tried placing two coolers behind monitor processing unit. After that monitor is realy cold, but still restarts constantly every 3 to 10 seconds. But before it starts reseting it work well at least two hours.
If you are competent with working on powered line voltage devices, you could use freeze spray on components that you suspect might be heat sensitive.

If you're not confident, stop here.

If you have no clue, you can freeze everything and try powering it up. Assuming the device powers up, you can then try the same with half of the components. Once you determine which half is suspect, divide that region in half and repeat the experiment.

Unfortunately, it's going to take time because you need a couple hours for it to fail after cooling down.

If you have a heat gun, you could use a similar technique to induce a failure.

It's going to be a pain in the a**. I have a monitor that does the same thing and it's not worth my time to troubleshoot.

From Jameco:
1663693718449.png
 

upand_at_them

Joined May 15, 2010
941
The screen going out after a short period is typical of a bad backlight. If this has CCFL backlight I would suspect that first. I recently fixed this very issue on a trash-found 22" monitor. I only had to resolder the connections to the CCFL bulbs. Not guaranteed to be your problem, of course. If you dig deep into the monitor be aware that cleanliness matters.
 

Thread Starter

Lightportal

Joined Oct 2, 2021
4
Welcome to AAC!
If you are competent with working on powered line voltage devices, you could use freeze spray on components that you suspect might be heat sensitive.

If you're not confident, stop here.

If you have no clue, you can freeze everything and try powering it up. Assuming the device powers up, you can then try the same with half of the components. Once you determine which half is suspect, divide that region in half and repeat the experiment.

Unfortunately, it's going to take time because you need a couple hours for it to fail after cooling down.

If you have a heat gun, you could use a similar technique to induce a failure.

It's going to be a pain in the a**. I have a monitor that does the same thing and it's not worth my time to troubleshoot.

From Jameco:
View attachment 276613
Thanks, for information I'll try.
 

Thread Starter

Lightportal

Joined Oct 2, 2021
4
The screen going out after a short period is typical of a bad backlight. If this has CCFL backlight I would suspect that first. I recently fixed this very issue on a trash-found 22" monitor. I only had to resolder the connections to the CCFL bulbs. Not guaranteed to be your problem, of course. If you dig deep into the monitor be aware that cleanliness matters.
I have tested with flash light and I don't see any image. Don't think it is the case.
 

crutschow

Joined Mar 14, 2008
30,791
Electrolytic capacitors are a possible problem.
You might try possibly replacing any that may be in the internal power circuit.
 
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