Did you also try different floppy drives? Or is that what you meant when you said drivers?

debs3759 wrote on 2023-11-04, 20:03:

Did you also try different floppy drives? Or is that what you meant when you said drivers?

My mistake, floppy driVES yes, i tried three different drives. Other than thatn, the motherboard is perfectly working under stress tests. Never happened before, usually i sometimes put the cable in the wrong side, but this time i tried every combination

What mainboard is it? And what Super-I/O chip??
In case it´s a Winbond "W83757(F)" consider it broken.

majestyk wrote on 2023-11-04, 21:10:

What mainboard is it? And what Super-I/O chip??
In case it´s a Winbond "W83757(F)" consider it broken.

Hello, it's an MSI MS-6156 with the Winbond W83977EF-AW

Nothing to do, i spend another hour to try every possible combination but the "C0" error is always there, so the controller is most likely damaged. Even without anything attached on the board, the C0 error appears.

Every floppy works on others PC so it's pretty obvious, the last attempt i can do it's to wash accurately the motherboard with a PCB cleaner and hope for the best.

I had an identical problem on a 486 pci motherboard with a W83787F controller. Use an oscilloscope to see if there is a waveform on the quartz resonator (it should be 24MHz but yours may be different). I had to change the resonator and everything returned to normal. I don't rule out that you have a damaged IC controller, but it's worth check.

is green led on drive lighting constantly?

tomaszdko wrote on 2023-12-21, 16:43:

I had an identical problem on a 486 pci motherboard with a W83787F controller. Use an oscilloscope to see if there is a waveform on the quartz resonator (it should be 24MHz but yours may be different). I had to change the resonator and everything returned to normal. I don't rule out that you have a damaged IC controller, but it's worth check.

Those "modern" super I/O chips use the same quartz crystal for the processor clock of the floppy controller and as base clock for the serial ports. If the oscillator failed (which I had happen to me on a board corroded by a leaky Nickel rechargeable battery), not only the floppy drives stop working, but also the serial ports stop working. If the OP can get checkit onto that machine, it will fail the "serial port loopback test" if the oscillator doesn't oscillate. Simultaneous failure of the serial ports and the floppy interface would be a quite strong hint to check the crystal.

"Simultaneous failure of the serial ports and the floppy interface would be a quite strong hint to check the crystal." - that's true, but when I got the motherboard and saw the floppy drive error, I didn't associate it to the COM ports. I was looking for an integrated circuit that controls the floppy disk drive and the first thing I did was check the crystal (a habit when programming ATxmega microcontrollers) . But You are right , He can diagnose the error by checking the com ports. If they do not work, it means that the controller is dead and possibly replace the quartz resonator, check the connections to the PCB , checking the capacitors connected to the resonator.

Plugging the floppy cable in a wrong way (except the usual 180° turn with a permantly lit LED) is the most common cause for broken super-I/O chips.
Mainboards without plasic sockets around the connector pins are the typical candidates here. If someone plugged the floppy cable "out of pitch" in the past, like leaving pins on one of the ends unused the chip can easily be damaged.