UNSOLVED
Closed
Precision 7520 unusual LCD issue?
I’ve brought back a Precision 7520 parts machine from the dead recently and all was good until this morning. I’ve been running it daily off a docking station with 2 external monitors with no issue at home, today though I brought it to work with me and found that when connected to the wall with a PSU, the LCD begins to flicker like has been exhibited on machines with BIOS firmware issues. I did upgrade the BIOS yesterday to the latest version out there, and had no trouble until now, so I don’t believe it’s that. The issue does not occur on battery, only when the PSU is connected. This starts at boot, the Dell logo starts to flicker and glitch, and this continues into Windows. Disconnecting the PSU causes the issue to stop. Everything else seems normal, all softer runs as it should networking is connected, etc.
Possibly related: On first boot with the PSU plugged in, the battery showed a level of 35% and dropping. This should not have been, I had the laptop on the dock all night, and it was off the dock in my bag for about an hour before plugging it in at work. I shut down the machine, pulled the battery out, and tried booting with the PSU alone. The machine booted, the LCD flickering persisted. I shut the machine down, installed the battery, and with it off, I let it charge. The charge light indicated full charge in under 2 minutes. Booting back up, showed a battery at 100%, and it has remained around there.
I have yet to get home and pop it back on the dock and see if this replicates there at this time.
Could this be a BIOS firmware issue? Could there be an issue with the power circuit on the motherboard?
Chino de Oro
11 Legend
•
8458 Posts
•
46451 Points
85
0
Posted April 25th, 2023 21:00
Sound like a good place to start. Inspect the power connector port, reseat and observing for any possible sight of short circuit.
Check battery health status and run calibration so operating system can get a baseline. It helps with charging status and accuracy in reporting of battery level.
Battery health is excellent, it’s brand new, albeit it’s an aftermarket battery rather than a a Dell genuine part. Can I run calibration on an aftermarket battery? Seeing as the laptop runs normally with the battery alone, and still acts up with the battery removed and the PSU alone, I suspect it’s not the issue here.
The power port connector though: I’ll pull it out and check it, but I did reseat it and its motherboard side connector yesterday, that didn’t improve anything. Worth a more detailed look, perhaps a replacement port assembly.
Mainegrw
3 Posts
93
0
Posted April 25th, 2023 17:00
Update: I just popped the laptop back onto my home docking station, it works as it should, though the screen was a little glitchy until the two external displays popped up, i.e. from the Dell logo popping up at first boot, to windows login screen, it was lightly glitching, then total normalcy. I did a second boot, that time no glitching at all on the dock. I should also note that I ran the machine plugged in for a while at my desk, eventually it settled down and by and large stopped glitching with a few blips here and there. Not sure what to think.
I did also run the browser-based diagnostics and testing utilities on the Dell Support site, the machine came back with a clean bill of health across the board, so not sure this is a hardware issue. I ran that while the machine was plugged in to a PSU and not my dock.
Edit to add: also tried the second PSU I have connected to my dock directly into the laptop charge port, same problem, occurs, glitching lightly not quite as bad as it was earlier today, but still occurring. I also tried a third PSU my IT person had at work, same deal.
is there a chance that the cable connecting the power port to the motherboard is causing interference with the display hardware? It does run awfully close to my SSD, also grounds to the same area of the chassis where the screen mounts…