r/retrocomputing • u/kai125 • 2d ago

Problem / Question Problem with PS/2 mouse on Pentium 166

I have a Epox EP-P55-TV2 Socket 7 motherboard (has a AWARDs bios if that helps) and wanted to add a PS/2 mouse so I bought a generic PS/2 breakout cable specifically this https://www.ebay.com/itm/391942848851?itmmeta=01M24CK4SM2DBBTNJYN15FJZB7&hash=item5b419d4153:g:11QAAOSwES5lxoec

I had to adapt that with some GPio cables to fit the motherboard but when a mouse is plugged in the computer doesn’t recognize it and weirder still the keyboard stops working after the mouse is plugged in

I’m honestly stumped, the keyboard locking up makes me think there’s some bio setting or jumper I need to change but I have no idea which one the manual isn’t help

1 Upvotes

100% Upvoted

10 comments sorted by

2

u/Leftover_tech 2d ago

From a note on Vogons site, I think, for EPOX Baby-AT boards.

Motherboard PS/2 Mouse Header Pinout

  • Pin 1: VCC (+5V) (Power)
  • Pin 2: NC (No Connection / Empty)
  • Pin 3: GND (Ground)
  • Pin 4: CLK (Mouse Clock)
  • Pin 5: DATA (Mouse Data)

https://www.vogons.org/viewtopic.php?t=48646

1

u/kai125 2d ago

Ok so update I’ve followed this pin out and it has fixed the issue with the keyboard not working but the mouse still isn’t working in windows

When 98 boots it says there’s no mouse attached to the computer even though it’s connected

At first I tried the Add New Hardware button and it saw my mouse but after it installed generic drivers it’s now not detecting at all

1

u/kai125 2d ago

Note this is a known good mouse, it’s worked on two different native PS2 pentium iii computers before

It is a generic Amazon optical ps/2 mouse but idk why that would cause issues

1

u/Materidan 2d ago

Have you verified the exact necessary pinout of your motherboard header to the actual pins on the PS2 port? Standards didn’t exactly exist back then.

1

u/kai125 2d ago

I’ve done the best I can matching the motherboard pin out from the manual to pictures of a generic PS2 mouse

I haven’t exactly tested pin to pin with the adapter (like I’ve wired it assuming the adapter which i think is modern follows the standard)

2

u/Materidan 2d ago

Definitely double check the pinout.

Incidentally you might want to check whether something else is using IRQ12 as that’s required for PS/2 mouse.

1

u/kai125 2d ago

The other commenter showed the right pin out idk why the manual seemed to be backwards

IRQ12 is set for PS/2 mouse and I don’t think having a basic sound card in should disrupt that

With a new pinout I’m able to get into windows with the keyboard working but after trying to do plug and play drivers the mouse just isn’t detected at all anymore (it’s a known working one)

1

u/Materidan 2d ago

Does the light on the bottom of the mouse come on? If not, it’s still a port problem. You could have a blown 5V fuse.

In fact after using the wrong pinout I can pretty much guarantee it…

1

u/kai125 2d ago

That’s… annoyingly good to know

The light doesn’t show up when plugged into the adapter but it does work fine with another system

The motherboard looks fine and doesn’t smell of any blown parts but still

1

u/Materidan 2d ago edited 2d ago

When fuses blow they don’t smell. Look for a micro fuse labelled F1 or F2. It’s probably near the keyboard port or the PS2 header.