PS/2 port issues.
Posted by Dehydrated_Lemur@reddit | vintagecomputing | View on Reddit | 37 comments
Currently having issues with these ports on my AOpen X34-U board. When I boot with just the ps/2 keyboard and a USB mouse everything works. When I try to use a ps/2 mouse and a ps/2 keyboard neither one work and the bios cries about no keyboard being attached.
Are these ports specific to the mouse and keyboard? I mean, can I try to put the keyboard in the mouse port and will the bios recognize it? If that's possible that may be a good way to determine if the mouse port is bad.
I did confirm that there are no cracked solder joints as I reflowed them. If the mouse port is bad, what are repair options? Is it the port itself that I can just replace or components down the line?
PublicAd4857@reddit
Switching your mouse to PS2 mode? Old mice had serial/ps2 switches. The serial-ps2 adapter is just rewiring. Attaching serial mouse with adapter in serial mode will hang the mobo.
Dehydrated_Lemur@reddit (OP)
My ps/2 mouse does not have a switch.. it is only a one way street
PublicAd4857@reddit
Find another tested ps2 mouse. This whole story sounds like a bad mouse.
Dehydrated_Lemur@reddit (OP)
I cannot rule that out as I do only have 1 PS2 mouse.
PublicAd4857@reddit
Get a multimeter and look for shorts inside the mouse.
Dehydrated_Lemur@reddit (OP)
So I did a quick test in-between work. I did not have much time so it was really quick and not scientific at all. I have a ps/2 to USB dongle.
I plugged the ps/2 mouse into the dongle and plugged the dongle into the USB port. The mouse did not work there either.
I have never used these dongle before so I cannot confirm if the dongles work or not (they're brand new and just came in the mail) but reviews from others say they work. When I finally have weekend time I will tear the mouse down and possibly buy another mouse.
I think it's a good start though
PublicAd4857@reddit
Old ps2 mice will not work with USB dongle. The mouse recognizes the connection type. USB, serial, ps2 are completely different animals. What mouse do you have?
Dehydrated_Lemur@reddit (OP)
I used a USB mouse into the dongle and connected the dongle into the PS2 port
PublicAd4857@reddit
What is this mouse? If it's a new USB mouse it won't work as ps2. The dongle is just a rewiring again, nothing else. Older MS USB mice worked with the dongles from late 90s or ealry 2000.
Dehydrated_Lemur@reddit (OP)
🤔 I'm not sure exactly how old it is, but I think it's most likely newer than 26 years. That's probably the issue with that in this case.
PublicAd4857@reddit
What brand? Bar code on the bottom?
Dehydrated_Lemur@reddit (OP)
Okay I just got home and was able to look at the hardware. The dongle I use allows me to plug a PS2 mouse into USB. Not the other way around 🤦. This doesn't work and when my PC boots it says no mouse detected. Doesn't do me any help considering I have only one PS2 mouse. I will need to source another to try with to confirm the only PS2 mouse I have isn't the issue here.
PublicAd4857@reddit
I need to see the mouse...
Dehydrated_Lemur@reddit (OP)
https://imgur.com/gallery/SSAziNA
Sorry about that
PublicAd4857@reddit
Is this the mouse which works with the dongle in the USB?
Dehydrated_Lemur@reddit (OP)
No it is not. This is the mouse that when I plug into my PS2 connector it kills both ports (noise and keyboard).
When I take this mouse with the USB adapter on and try it in the USB port, it still doesn't work.
I only have 1 PS2 mouse and due to work, I haven't been able to get another yet but this weekend I will.
My actual USB mouse works fine in the USB port with my PS2 keyboard. As soon as the PS2 mouse goes it everything breaks.
PublicAd4857@reddit
Yeah, get another one.
Dehydrated_Lemur@reddit (OP)
different mouse works. Thanks
PublicAd4857@reddit
Good.
Dehydrated_Lemur@reddit (OP)
Apologies. Here
https://imgur.com/gallery/dcKAzlp
PublicAd4857@reddit
Newer versions work, late '90s. What kind of ps2 mouse are you trying?
songoffall@reddit
There isn't supposed to be crosstalk between the PS/2 mouse and keyboard on data lines, so maybe the mouse port's power line is shorted?
Dehydrated_Lemur@reddit (OP)
This is very possible. When I have time in-between work, I will tear the mouse down and see if anything is sus in there.
songoffall@reddit
There's something else that came to mind. There's often a jumper on later PS/2 motherboards that selects whether 3.3v or 5v power is sent to the PS/2 port. Some older mice and keyboards would require 5v power to work, so you might also check if the port provides 5v or 3.3v. I went through the manual and it did not mention such a jumper on your motherboard. So maybe it's 3.3v only, and you are using an older peripheral that requires 5v, which might cause the problems you described.
Boring-War-1981@reddit
Do they? I can use a mouse designed for the first PS/2 system on every board I’ve got
songoffall@reddit
I would assume your mice are from 90s then.
Boring-War-1981@reddit
Got a few, oldest is an IBM designed for the PS/2 systems, the more rounded design that I think was 89 could have been earlier.
songoffall@reddit
I might be misremembering things then.
Dehydrated_Lemur@reddit (OP)
super interesting. I did not know that. And I don't have my mouse in from of my at the moment. I do wonder if it says the required input on the mouse but I doubt it. I'll keep this is kind also! Thanks a ton.
balding_git@reddit
the bad cap on the right and probably others are a likely cause
Dehydrated_Lemur@reddit (OP)
No this is a photo taken from before I replaced them all.
balding_git@reddit
in that case, you should be able to swap the port with no problems of you have a spare, id probably start with that just to rule it out.. beyond that maybe chipset? not sure where the logic goes..
vraptor1064@reddit
It may just be the picture ... But the small capacitor at the top behind the ps2 port labeled c1 looks a bit odd ... Like the PCB is darker through the middle of C1.. if you have a multimeter... Pull power from the mobo, toggle the PC power button to drain power, then put the multi meter in continuity mode and test across C1 it should be open. If the test shows a short then either c1 or the board around C1 is shorted.
randomataxia@reddit
Be sure to shut the system completely down, then attach the keyboard and mouse. PS2 ports aren't like USB, you're not supposed to connect/disconnect them with the system powered up.
Make sure you're matching the correct port for the correct peripheral as well. Purple for keyboard, Green for mouse.
Some boards also may need a BIOS toggle to enable the ports.
Dehydrated_Lemur@reddit (OP)
Can confirm I don't hot swap the ports and did everything else you mentioned.
Lumornys@reddit
Most mainboards will not recognize a PS/2 mouse or a PS/2 keyboard if it's plugged into the wrong port.
The PS/2 port that is closer to the PCB is for the keyboard, and the one stacked on top of it is for the mouse.
majestic_ubertrout@reddit
I've found that PS/2 sometimes either won't work or won't work if you've been using USB until you reboot a few times with PS/2 connected. Not sure why.