You could be in luck with the Dallas battery, looks like the mod to hook up a coin cell battery to replace the internal battery. If the Dallas battery is soldered to the motherboard, this is pretty handy.

I have Seventeam power supplies, they always struck me as good quality, but others might know better. In fact the only 300W AT supply I have is from Seventeam. There were certainly lesser generic brands from that time.

Brickpad, the guy with the same machine, might be able to help you set the MHz display, but I've also got a display with DIP switches (different layout though) which seems to be uncommon. The one in my desktop uses segment combos to create numbers, instead of mapping each switch to an individual segment. It took some trial and error to get it working. Hope yours is easier to configure. Nice system, by the way!

After bit of testing the computer seems to work except couple of things. When I set the year to 2018 in bios, the next time I go to bios it is changed to 1998, which I assume means that it only knows years from 1980 to 1999?
Another thing is that 5 1/4 floppy drive is detected normally, but when I put in a disk and in dos try to see what is on a disk, the output looks like this:

I assume there is no way to fix the floppy drive?

Would anyone happen to know where to find jumper settings for the I/O card that came with the PC? It happens to have a joystick port at the back, so I think I would have to disable it to be able to try installing any sound card to the system.

Baoran wrote:

After bit of testing the computer seems to work except couple of things. When I set the year to 2018 in bios, the next time I go to bios it is changed to 1998, which I assume means that it only knows years from 1980 to 1999?

Year 2K issue: https://en.wikipedia.org/wiki/Year_2000_problem

Also, your system appears to have EISA slots (SCORE!). That may mean that the I/O card and VGA cards are actually 32 bit EISA cards.

There were many versions of that. The contents of the box with "PX" on yours changes between them.
I do not know if the different versions have different jumper settings.
This one states the PX so it's yours.
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Back just before Y2k there was a test all over the web to check BIOS for compliance.
You can still find it here and there but it might take a while.
The Vogons Driver Library here might even have it. Never checked.

I'm thinkin' your CMOS battery and that floppy disk (not drive) are the problems.
.
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I tested things bit further. It seems that I get similar problem with 3.5" floppy drive too and the problem is still there even if I switch to another I/O card. Only thing I can think of that there must be something wrong with the motherboard itself.

Try a new CMOS battery. Your RTC may be screwing up.
The date reset also can be a bad CMOS battery.
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It does keep all the settings in bios though like hard drive and floppy drive type settings. It even keeps day and month in the date, it just always just changes 2018 to 1998

Set your date in DOS using the "Date" command and see what happens.

After I set the year to 2018 in bios, the date stays 2018 in dos until I enter bios again and then it changes to 1998 in bios.

Make date 2018 in DOS.
Reboot without going into BIOS.
What is date in DOS now?
.

Baoran wrote:

After I set the year to 2018 in bios, the date stays 2018 in dos until I enter bios again and then it changes to 1998 in bios.

Not sure, but it seems like your BIOS / CMOS setup (or less likely Real-Time Clock) is able to handle two digits only. 😐
Since 486 machines are about the transition between old and new, it perhaps interprets 2018 as 1918, an invalid date.
Normally, it should go back to 01.01.80 or something like that, though. (19)98 is a bit unusual.

More recent BIOSes do interpret two digit numbers between 00-79 as 20xx and 80-99 as 19xx.
Windows/MS software on the other hand, will interepret anything ~00-29 as 20xx.
(Speaking under correction.)

Edit: Edited.

If I set date in dos, it stays correct after a boot or after turning off the computer. Only entering bios changes the date to wrong one.
Could the problem with floppy drives still be battery related?

I don't know for sure, but I think that's normal behavior, don't worry.
DOS will accept any time/date the real-time clock the is set to.
At least MS-DOS 5 and higher. Not sure about the earlier or other versions. 😕

I don't think floppy drives not working is normal behavior. In any case even if the motherboard is bad, I think I got my money's worth. The case looks to be in really good condition and power supply has good voltages too.

Baoran wrote:

I don't think floppy drives not working is normal behavior. In any case even if the motherboard is bad, I think I got my money's worth. The case looks to be in really good condition and power supply has good voltages too.

He was talking about the time only.

I don't think the motherboard is bad either.
Maybe RAM, Cache, Cable.

If Ram or cache would be the problem, wouldn't it affect things when using hard drive as well? All the programs on the hard drives seem to work fine.

Baoran wrote:

If Ram or cache would be the problem, wouldn't it affect things when using hard drive as well? All the programs on the hard drives seem to work fine.

If that's true it's the same for the motherboard. If the mobo is doing it why isn't the HDD affected.