On 03/18/2017 04:06 PM, bitrex wrote:
I have a used Dell Inspiron 5558 laptop, which didn't come with an OEM
power supply. I picked up a 65W "universal" type for it off Amazon, and
it's showing some weird behavior.

First problem is that it often refuses to charge the battery when
connected to line power. Maybe 1 out of 10 times I've plugged it in the
battery charges, the other times the charging LED remains off and the
charging indicator on the screen remains at 0%.

It sometimes has difficulty starting up from line power at my home as
well; you have to hit the power button a couple times to get it to power
on instead of coming up for a few seconds then immediately shutting
down. However, it seems to always work fine off the local Starbuck's
wall power. Still doesn't charge properly, though.

The BIOS reports some incidences of "Unknown AC adapter detected!" but
not all the time.

Before I run out and make sure to pick up an OEM supply, is there any
way to ensure this is certainly a problem with the adapter and not the PC?

Maybe a BIOS update is required?

So here's the final solution. The new power adapter powered the laptop
consistently, however it only charged the battery once. Then it refused
to charge again.

Updating the BIOS to the latest version fixed that problem as well, so
now everything is working fine. I had to use the "hack" method though,
as of course I didn't realize there was a problem remaining until the
battery had fully discharged, and the Windows update tool requires the
battery to be above 10% to operate, as "ohger1" mentioned.

For future reference, you get Dell Diagnostic Deployment Package (DDDP)
he

https://www.dell.com/support/article/us/en/19/SLN143196/how-to-create-a-bootable-usb-flash-drive-using-dell-diagnostic-deployment-package--dddp-?lang=EN

and also the latest BIOS update executable. Follow the instructions to
make a bootable USB flash drive with the proper DOS startup files.

Hit F12 on startup and switch the boot mode from "UEFI" to "Legacy."
Restart and select the USB flash drive to boot from and a DOS prompt
like "Diag C:\" should come up.

The BIOS update file will show up with the usual "~1" at the end to
represent an extended filename. On mine it was "INSPIR~1.EXE". Type
"INSPIR~1.EXE /forceit" (hidden option) to force a BIOS update while on
AC power with a dead battery.

After the BIOS is flashed shut down the computer, remove the battery and
hold down the power switch for about 20 seconds. Reboot, switch the boot
mode back to "UEFI" and boot into Windows and the charging light should
come on indicating the battery is charging properly. Yay!