This topic came up here: How to fix your dead on-board floppy controller

The motherboard seems to have pc87312vf super IO chip that controls serial, parallel and ide ports as well. Since everything else except floppy seems to work it does not seem as the chip itself is dead at least.

I finally managed to attach a picture of the motherboard after taking another picture. Perhaps there was something wrong with the file itself when I tried previously

What CPU are you using? AMD CPUs (Enhanced 486 and 5x86) can cause the floppy to fail if cache is set to WB.

derSammler wrote on 2020-02-16, 09:27:

What CPU are you using? AMD CPUs (Enhanced 486 and 5x86) can cause the floppy to fail if cache is set to WB.

I just tested it with kingston turbochip because I don't have manual for the motherboard. As far as I know you don't need to configure the cpu using jumpers when when using kingston turbochip and it can accept different voltages.

But isn't that an Am5x86?

Try a different CPU if possible. You don't need the manual, all jumper settings are written onto the mainboard.

Kingston TurboChip is AM5x86, for sure you have Wrong Cache Setting/Jumpersetting on your Mainboard.

Check with a 5V CPU, DX2 66 or DX33 from intel.. if floppy works you know what the problem is.

derSammler wrote on 2020-02-16, 10:07:

But isn't that an Am5x86?

Try a different CPU if possible. You don't need the manual, all jumper settings are written onto the mainboard.

There are more jumpers on this motherboard than I have seen on any other. Main problem is the voltage. I don't have resistor pack? needed to set RN18 or RN19 and I assume those are for setting voltage/cpu types.
I think with kingston turbochip it forces L2 cache to write through at least because of compatibility with older motherboards, but not sure about L1.

You don't need to care about voltage if you test with a 5V CPU.

matze79 wrote on 2020-02-16, 10:10:

Kingston TurboChip is AM5x86, for sure you have Wrong Cache Setting/Jumpersetting on your Mainboard.

Check with a 5V CPU, DX2 66 or DX33 from intel.. if floppy works you know what the problem is.

Looks like you are correct. No more floppy disk fail with 486dx 33Mhz cpu.
Is there any way to get floppy drive to work with the turbochip?

Nevermind. Even if I don't get floppy drive fail error during post, it won't read any floppies. "Not ready reading drive A" error

Edit: It is reading floppies now. Good to know that there is actually nothing wrong with the motherboard itself. That "Not ready reading drive A" error was fixed when I did "Load bios defaults" in bios settings, so I don't actually know what setting caused it. There are so many more options in this bios compared to my other 486 motherboards so I don't know what all of them mean.

I really don't understand these old motherboards sometimes. After I did load those bios defaults, no matter what settings I change in bios it doesn't seem to make the floppy drive stop working again. Even putting back that kingston turbochip doesn't make the floppy drive stop working again. Perhaps I have missed some specific setting that was wrong in bios when I had all that trouble with it.

The kingston turbochip seems to be really slow on this motherboard though based on some dos benchmarks. Norton sysinfo says it is even bit slower than 486dx2 66Mhz for example. On most other motherboards it is close to or beats 486dx4 100Mhz.