VOGONS


First post, by GoblinUpTheRoad

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A while back, after playing games on my 486 off and on for several weeks, suddenly my mouse stopped working. Tried using another mouse and it too wouldn't work. Next I swapped out the I/O card with another and still the same, not working. I put the orignal I/O card back in, but this time I moved it to a new ISA slot and the mouse started working again and all was good.

Fast forward a few months and the same thing happened again. I moved the I/O card to all the different ISA slots, tried different mouses, different I/O cards but can't get the mouse to work. Tried to use COM2 port but still nothing.

Cutemouse drivers load fine but Microsoft Diagnostics says that the mouse is 'Not Detected', and IRQs and stuff looks good.. Microsoft's MOUSE.COM won't load, says no mouse found.

I've confirmed the mouses and I/O cards work fine in my other systems, so I think it has to be the motherboard. The hard drive, CD-ROM, and two floppy drives all work fine off of the same I/O card, but it seems strange that it is isolated to just the COM ports as everything else in the system is working fine.

Does anyone with a deeper knowledge of how the ISA BUS works have any guesses as to where the problem might be? Can anyone recommend some more ways to test?

Reply 1 of 5, by Baoran

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Perhaps it is irq line problem for the serial ports? I have had irq line of a floppy drive touching the pin next to it in the irq controller and causing weird issues, so I assume it could cause something like that if it happened to irq lines of serial ports.
Probably could be lots of things, but this is the first thing that came to my mind.

Reply 2 of 5, by dondiego

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Probably the -12V voltage is not reaching the serial port due to some mobo damage, you should check with a multimeter. Pin 5 is ground. Similar problem here:
Mouse not working with 386 mobo

LZDoom, ZDoom32, ZDoom LE
RUDE (Doom)
Romero's Heresy II (Heretic)

Reply 3 of 5, by GoblinUpTheRoad

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Thanks dondiego, -12v looks to be the problem, reads 0.61v at the card. I have cleaned and repaired battery damage on this board before so I guess I didn't do a good enough job on that.

Reply 4 of 5, by GoblinUpTheRoad

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Whoops! I got my traces confused and accidently hooked up the -12v to the +12v line and blew a cap on the mobo 😳 Didn't do any other damage luckily, replaced the cap and was back where I started. I found the correct trace and everything looked like it was connecting OK 😕 Powered it up and still no -12v at the card 😕 😕 After a bit more digging, turns out the -12v pin inside the power supply plug had broken in half and wasn't connecting 😊 Such a simple problem, don't know why it was so hard to find... Fixed now and everything working good 😁

Reply 5 of 5, by GigAHerZ

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I hate those -12V problems... My journey is here: [FIXED] Serial ports both dead? (Acorp 5VIA3P / EFA P5V580)

Good to hear you have successfully diagnosed the problem. (Y)

"640K ought to be enough for anybody." - And i intend to get every last bit out of it even after loading every damn driver!