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Old 07-31-2021, 05:01 AM   #6
mattie47
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Join Date: Jul 2021
City & State: Christchurch
My Country: New Zealand
I'm a: Knowledge Seeker
Posts: 5
Default Re: Dead Dell P2416db - No standby/power LED detected

Unfortunately this story has a sad ending.

I managed to borrow a working monitor of the same model to try narrow things down.

It turns out, after plugging in the "dead" monitor's panel, that not only would it get no power, but the person I got it off damaged the panel

Despite this, I thought I'd check a few things on the "working" monitor.

Turns out with the "working" monitor:
- mcp2315 also has no power coming out of it. This only would enable power when the power button is turned on. Secondly 10v *is* correct for this rail.
- The LDO mentioned previously with 3.3v also has no VOUT when the monitor is off. Only when turning monitor on, does this have 3.3v coming out of it.


Regardless - I think I've found a short to ground. I noticed the "working" screen 's heatsink didn't appear to be heating up in standby like the "dead" screen.

I then had a look on the other side of the board.

See attached pic "short". There's a red line of drawn on a VIN pin which is hitting continuity when I attach to ground. This wasn't the case with the "working" screen.

Right in the center, I noticed some of the caps seem to get a little bit warm.

Correct me if I'm wrong, but using a bench power supply set to say 3v, 3amps, and injecting power somewhere on the board should cause the problem component to heat up right? I.e. could then use some IPA to see where it dissolves? I don't have my bench PSU handy, so haven't tried this yet.
Attached Images
File Type: jpg 224888293_424429682434708_528518152255163594_n.jpg (215.6 KB, 4 views)
File Type: jpg short.jpg (662.4 KB, 10 views)
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