Odd. Do you have access to any other machine to check the mouse is ok? Also, I think I've read somewhere that some mice could change protocol if you hold down the left button when turning the machine on, so maybe try that. Does it help if you pull the sound card out?

Maybe try an other serial port or an other device. (Often these things are not hot plugable.)

What IRQ and I/O ranges is the sound card using?

What happens if you remove the sound card?

Thanks for the help. I tried all above suggestions (holding lmb while booting pc, and to boot the pc without the sound card) unfortunately it still says no device found. I don't have access to another pc but a new mouse is on the way, so I can see whether the problem lies with the mouse or the pc.

Through this forum I found the tool Snooper which shows the current ports, channels etc and which ones are in use, attached is a photo of what it shows.

Edit: For the completeness I also added pictures of my startup screen, showing what channels the sound card is using, and the autoexec.bat and config.sys file.
As for the autoexec.bat file, as you can see I put ctmouse on top as I was curious if it would work before loading the sound drivers, but it doesn't make a difference.

I have three identical multi io controllers from Vtech. These all have two serial ports on our. Jumper settings are on th9o and are confirmed to be set as requested. One card refuses to detect anything from the serial port. I think t saw two or three bad caps on it.

That may be the reason for my device. For yours it may also have to do with caps running end of life, and just passed the threshold.

Hmm interesting. Is there a way I can see if one or more capacitors are dead? I have to add though that this i/o controller was never used before (I was lucky to get my hands on some new-in-the-box parts).

What would cause it to die so quickly if that is indeed the case?

Hi! I recommend running CheckIt! and MSD, too!

CheckIt! can do test the serial ports, to some degree even without a loop-back adapter.

While MSD does detect a mouse even without a mouse driver loaded.
Provided, that it knows the mouse protocol of the mouse..

Tried /s/m or /m/s?

Got the new mouse, also doesn't work.

I attached photo's of my I/O Controller card that the serial port is on (CN4 in this case)

Also found a PDF but I don't really understand the jumper settings, maybe someone else can make something of it? https://www.elhvb.com/iocard/tdnservices/pt606.pdf
I have to add that, in my case, JP6 had to be set to pin 2&3 otherwise it wouldn't detect my hard drive. I thought this was weird as, if this PDF is indeed for my card, it means it would now be disabled.

Tbh this card has been giving me issues from the start. For example the floppy drive wouldn't work because one of the pins was much longer than the others, so I had to push the jumper down with some force and only then it would work.

@Jo22:
I hadn't heard of Checkit or MSD before, so I can run those too if you think it could be useful? I will do that later when the card is in the pc again.
@Nexxen: Yes, tried basically all combinations. At some point it installs the driver but the mouse doesn't work (or it jumps to corners of the screen when I move it a lot, so it's detecting something

Sometimes you can see if a cap fails. It shows cracks or seems a bit burned black/grey-ish. But more than often they fail without any sign and you can only tell with a multimeter or other testing gear.

In you're case I can't see any evidence so they might just fall internally.

Given the age and current failure, it could be wise to just replace all of them, the "103" labelled ones. They're cheap and will run for another 20-30 years on. So hopefully that solves the failure.

Are the resistors r44 and r34 near the db9 connector ok?, they look craked from my point of view.

I noticed that as well! Especially R44. The brown "casing" is cracked and coming off. The one next to it (R43, but maybe you meant that one?) also looks a bit damaged. I don't know anything about them though, is it bad? Is it easy to find replacement resistors?

Edit: Attached a better photo of the potentially bad resistors

In the photo of the board the if I'm counting correctly it looks like it's JP5 set to 2-3, with JP6 set to 1-2? If that settings sheet is correct then JP5 on 2-3 disables the external serial port.

[I'm guessing those resistors are pull ups for the game port switches. If you're not using the gameport, try setting JP7 to 2-3 to disable it].

Maybe helps you, maybe someone else, but i've gotten quite an headache from somewhat simple problem:
Check that negative 12V is properly coming out from PSU and also check that you see it in COM port, too. 😉

@snufkin, no the counting is the other way around 😀 But you can't see that on the photo. So JP6 is set to 2-3, all other jumpers are set to 1-2

@GigAHerZ: I think I found your topic earlier 😀. I don't see anything strange, how did you find out that it wasn't working properly? The negative 12V I mean

Niborius wrote on 2022-05-17, 15:05:

@GigAHerZ: I think I found your topic earlier 😀. I don't see anything strange, how did you find out that it wasn't working properly? The negative 12V I mean

There just wasn't negative 12V coming from the PSU i was using at that time. And that is used for the serial port to work.
I used a multimeter to find it out.

Update: I got my hands on a different I/O HDD/FDD card with also a 9-pin serial port.

New weird issue: It seems to conflict with my screen/graphics card. I get one of these 3 situations when I boot the PC with the new card in:

1: System gives 2 long and 8 shorts beeps, nothing on the monitor
2: System doesn't beep, monitor goes on, but no image
3: Monitor goes on but the image is wrong (letters missing or looking off, screen filled with dashes, and games would show odd pixels (mostly the mouse would leave traces of pixels behind)

And yea that's right, at least the mouse works now 😜

I checked the cable connectors and they seem to be in just fine (can't push them in more). I think the card goes in the slot fine but I'm not 100% sure, I wonder if the metal bracket is in the way? But if I look carefully it doesn't look like it could go in more anyway. I tried different ISA slots but I get the same results.

Another update: Checked the voltages coming from the PSU and it shows normal values.

Found out that the PC (and screen) works as soon as I unplug the CF Card reader

Got my hands on a new CF Card Reader, new IDE cables and also tried a new CF card, but again, I get the beeps and no screen at all. I'm at a loss

Niborius wrote on 2022-06-10, 13:04:

Found out that the PC (and screen) works as soon as I unplug the CF Card reader

Got my hands on a new CF Card Reader, new IDE cables and also tried a new CF card, but again, I get the beeps and no screen at all. I'm at a loss

Hm. Are you sure the orientation of the CF card is correct?
- Some CF to IDE adapters are weird. 🤷‍♂️

Also, some cheap CF to IDE adapters do have shorts (on the back of the CF socket).
You may wish to check the adapter's PCB with a magnifying glass.