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Old 03-19-2022, 05:59 AM   #1
nheather
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Default Have I Inadvertently Fixed My Dell Ultrasharp U2312 Monitor

For the last few weeks I have been trying on and off to fix my Dell Ultrasharp U2312.

I'd read that the 1084-33 voltage regulator on the logic board often needs replacing but they are pretty difficult to find in the UK, plus I don't have the hot air tools needed to replace it properly so I decided to check it instead.

It was getting a 5.16V input and a 3.41V output so that seemed fine so I started looking at the capacitors that I could easily and cheaply replace.

The symptoms were that the monitor would be perfect for a few minutes and then the flickering would start. It would start off with a single flicker maybe every 10 seconds or so but then they would get more frequent as the next few minutes passed until the point where the screen would go black for a second or two and then come back.

I'd swapped all I could do easily and cheaply so I then decided to solder some wires onto the two regulators on the logic board. They are both 3.3v but they are daisy chained the first with a nominal 5V input and a 3.3V output and the second taking that 3.3v as input so giving a 2.2V output.

All the voltages check out when I test on the board so with the test wires in place I hooked it up to the computer ready to start looking at the three voltage points (5V, 3.3V and 2.2V) when the flickering started.

But it doesn't flicker any more.

So could I have inadvertently fixed the problem.

Could it have been a simple dry joint that I fixed when I soldered the test wire onto the connection?

Could a dry joint on one of those regulators caused the symptoms that I was seeing?

Many thanks,

Nigel
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Old 03-19-2022, 06:28 AM   #2
stj
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Default Re: Have I Inadvertently Fixed My Dell Ultrasharp U2312 Monitor

could have been,
or heating the pin could have fixed the part.
i had that yesterday with a diode, it metered dead so i desoldered it and then it metered fine!
best to replace it anyway for reliability when you get the chance.
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Old 03-20-2022, 08:21 AM   #3
nheather
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Default Re: Have I Inadvertently Fixed My Dell Ultrasharp U2312 Monitor

Spoke too soon.

But strange - because before I put the test leads on it fault was reliably the same every time - would start after a minute or two.

But with the test leads in place it lasted about an hour before the same symptoms started.

I monitored all the regulator voltages while the screen was flickering and switching off (when I say switching off, I mean like lost video connection not powering off) and they were all rock steady.

So beginning to think that this isn't a power supply issue but maybe something in the video input (I'm using the display port) circuitry.

It's like it is momentarily losing video connection - sometimes so short it is just a flicker and sometimes a little longer to lose the display for a second or two.

Cheers,

Nigel
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