Questions: what operating system are you using? What is the history on this board - is it recently acquired with no background of how well it works, or is it one you've had for a long time and the ports have only recently begun acting up?

First port of call is the BIOS, ensure all USB options are turned on including USB keyboard and legacy USB.

USB keyboard usually works natively in DOS, USB mouse almost never. What OS are you using? Anything pre Windows 98SE will be a challenge.

was there corrosion inside the port? or did you scrape gold off? 😀
if corrosion then I would expect more on the board

The OS is Windows 98SE. I built the system around this board around a year ago with no prior use, and this is the first time I tried to use the USB ports. There are only two options that I found that regard USB: "Assign IRQ For USB" under "PnP/PCI Configuration" which is either Enabled or Disabled, set to Enabled, and "USB Keyboard Support Via" under "Integrated Peripherals" which is either OS or BIOS, set to OS. As for corrosion, since it is an old board, I thought cleaning the contacts would be an easy way to try fix the issue, I wasn't sure if there was any corrosion on the contacts but I doubt there is any left after a few cleans with deox and lightly sanding the contacts.

I think the next step would be to measure the USB port's voltage. Do PS/2 mice and keyboards work?

Repo Man11 wrote on 2024-04-21, 15:41:

I think the next step would be to measure the USB port's voltage. Do PS/2 mice and keyboards work?

Right, I'll be doing that next. The PS/2 ports have always worked just fine.

The ports put out a solid 5V, is there a sensible way to measure anything else with just a regular multimeter?

I did find a PCI USB expansion card, so I don't currently need the USB ports on the MB. Should I still be worried about some caps failing or preventing other possible damage to the board? I'd also still be curious about fixing the ports just for the sake of learning.

Does everything appear normal in Device Manager?

Nothing unusual as far as I can see. This is without the USB PCI expansion card I mentioned:

When I plug something in the MB's USB ports, the system locks up, and when I unplug whatever I connected, "Unidentified Device" briefly appears.

I would have a look at this site and see if any of the tips help you resolve the problem(s): https://web.archive.org/web/20050830004925/ht … 8seusbguide.htm

If it were me, I'd try installing Windows XP or Windows 2000 for diagnostic purposes. If the onboard ports work well with either of those operating systems then you know it's probably a driver/OS issue; if they still do not work then you know that it's a hardware issue.

Repo Man11 wrote on 2024-05-22, 21:38:

If it were me, I'd try installing Windows XP or Windows 2000 for diagnostic purposes. If the onboard ports work well with either of those operating systems then you know it's probably a driver/OS issue; if they still do not work then you know that it's a hardware issue.

Faster than installing XP or 2k: boot a Linux Live CD. Knoppix 4.x or 5.x should work fine on a system like that. If the hardware's OK, the mouse will work. If not, not.

I tested the USB ports with a USB tester that shows amps and volts from the port. The amp digits on the tester barely lit up, and the volts didn't light up at all. This would indicate that the ports don't provide enough power.

Don't forget that this board is from the era of Abit's capacitor disaster so capacitors are a very likely cause. I'd try another PSU just in case (it shouldn't make any difference if you're not experiencing any other problems) and then go for the capacitors.

Visually all the capacitors look good, so no obvious clues but they're still the most likely culprits. I'll try with another PSU and then start looking into replacing the caps.