HP Compaq Pro 6200 SFF USB not working

[Jerrod2]

I know its a rather old pc, but I recently purchased an HP Compaq Pro 6200 SFF only to find out that my keyboard was not working with it. Neither the BIOS nor the operating system would detect it; and I know the keyboard works with other computers. After doing some research I figured that somebody may have disabled the USB ports and I sought out to reset the CMOS. And after having done that and it not working still, I'm at a loss.

I was just wondering if anybody knew what was going on here.

[TheOldMan]

I see that PC has PS/2 ports which will accommodate PS/2 keyboard and mouse.  You could try that.

If the USB ports have been disabled, pressing the CMOS reset button and holding for 5 seconds should reset the CMOS to defaults and give you the USB ports again.  Is that what you have done already?

[Jerrod2]

Yes. I have tried resetting the CMOS, multiple times, using the onboard reset button; but to no avail. I don't currently have access to a PS/2 keyboard but I will try that at some point. I have also seen where I can attach a PCI-E USB card and use it instead.

If and when I get the problem figured out I will report back here because it seems like there is something else at play.

[TheOldMan]

It is possible to add the PCI card for additional USB ports, because of the problems presenting themselves.  It is strange that resetting the CMOS did not re-enable the USB ports, however.

[Jerrod2 · Accepted solution]

I discovered the issue. The keyboard I'm trying to use is a Unicomp Model M replica circa 2022 which uses a Raspberry Pi to communicate with the USB controller. I didn't find anything online to confirm this, but my theory is that it cannot communicate to legacy bioses.

After having connected this keyboard to yet another older computer and discovering that it had the same problem, I set about to purchase another keyboard and it worked.

[TheOldMan]

Good that it is sorted out.  Thanks for reporting back.

[MrNothing]

Hi there, I have been considering purchasing a Unicomp New Model M to use primarily with a HP Compaq dc7900 Ultra-Slim running Windows XP. This computer appears to be a similar model and era to yours. I am glad I found this post before ordering the keyboard and am now having doubts whether I should buy it. Was the keyboard you tried a Unicomp New Model M or a Unicomp Mini M? I have read that some Unicomp Mini M keyboards around that time had some issues with the controller card and firmware.

[Jerrod2]

I purchased a Unicomp New Model M with a manufacturing date back to the summer of 2023. In my findings, I did see that most people were having issues with the Mini M; but not one person stated that they couldn't control their keyboard under the bios. So whether it's related to my issue or not is up in the air. I can tell you that I suspect it may be the Raspberry Pi controller that they used; at least with my keyboard because apparently they have used different controllers.

Your best bet would be to ask them what kind of controllers they use and if whether they have tested them for compatibility with legacy bioses. I might have said go for a PS/2 variant but they seem to have discontinued those.

[MrNothing]

I decided to buy the Unicomp New Model M and it just arrived. Thankfully it works fine with my HP Compaq. I was told that Unicomp is using the previous controller design for the time being due to supply shortages of the Pico Raspberry Pi controllers. So it could be the Raspberry Pi controller that was the problem.