It might be worth trying to remove the Adaptec ontroller, then reset BIOS to defaults completely (clear CMOS jumper), then turn on, enter BIOS and just disable onboard Floppy controller, power down, insert the Adaptec controller and restart.

If there´s no solution, why not live with the onboard FDC? There should be no big difference.

Also don't see the added value of using the AHA-1542B FDC...

However I do see what the problem might be: the AHA-1542B is non-PnP. You've set default jumpers on the card, but the BIOS has no way of knowing what they are. That will only work if you reserve the resources (particularly IRQ) in BIOS for "Legacy/non-PnP", otherwise the IRQ is listed free for allocation to (PCI) devices. As you don't mention that, I'm assuming you haven't done so. Try reserving the configured resources in BIOS and see what happens. Might just work. Btw default IRQ for FDC is IRQ 6, so if everything is default, that's the one to reserve. You might also need to reserve memory range.

majestyk wrote on 2021-01-28, 09:18:

It might be worth trying to remove the Adaptec ontroller, then reset BIOS to defaults completely (clear CMOS jumper), then turn on, enter BIOS and just disable onboard Floppy controller, power down, insert the Adaptec controller and restart.

If there´s no solution, why not live with the onboard FDC? There should be no big difference.

I've tried that still no luck. Asus P2B rev.1.12 doesn't have clr CMOS jumper so I unplug it and remove the coin cell for 1 hour.

dionb wrote on 2021-01-28, 11:08:

Also don't see the added value of using the AHA-1542B FDC...

However I do see what the problem might be: the AHA-1542B is non-PnP. You've set default jumpers on the card, but the BIOS has no way of knowing what they are. That will only work if you reserve the resources (particularly IRQ) in BIOS for "Legacy/non-PnP", otherwise the IRQ is listed free for allocation to (PCI) devices. As you don't mention that, I'm assuming you haven't done so. Try reserving the configured resources in BIOS and see what happens. Might just work. Btw default IRQ for FDC is IRQ 6, so if everything is default, that's the one to reserve. You might also need to reserve memory range.

I don't mention that but I checked that all the settings (IRQ, DMA, ...) are ok.
I think that is a motherboard problem, when I remove the Adaptec ISA controller and disable fdc in bios the pc doesn't boot.

Did you reflash the BIOS?
Or tried an earlier version?

lazaj30 wrote on 2021-01-28, 12:06:

[...]

I don't mention that but I checked that all the settings (IRQ, DMA, ...) are ok.
I think that is a motherboard problem, when I remove the Adaptec ISA controller and disable fdc in bios the pc doesn't boot.

Eh, that's weird, but clear enough: if it still fails to boot with AHA-1542B removed, then it's definitely in the motherboard.

On thing to try: ESCD reset - ESCD is where PnP stuff is stored. You do that reset by physically unplugging power from the PSU, then pressing the power button for >=5 sec (10 sec is recommended to be sure).

lazaj30 wrote on 2021-01-28, 12:03:

Asus P2B rev.1.12 doesn't have clr CMOS jumper so I unplug it and remove the coin cell for 1 hour.

Some ASUS boards of that generation do not have a jumper but they do have two solder pads marked [CLRTC] wich stands for 'clear real time clock'.
According to the manual of my P2B-S you should:
-turn off the computer and unplug the AC power
-short the two solder points labeled CLRTC

dionb wrote on 2021-01-28, 12:17:

lazaj30 wrote on 2021-01-28, 12:06:

[...]

I don't mention that but I checked that all the settings (IRQ, DMA, ...) are ok.
I think that is a motherboard problem, when I remove the Adaptec ISA controller and disable fdc in bios the pc doesn't boot.

Eh, that's weird, but clear enough: if it still fails to boot with AHA-1542B removed, then it's definitely in the motherboard.

On thing to try: ESCD reset - ESCD is where PnP stuff is stored. You do that reset by physically unplugging power from the PSU, then pressing the power button for >=5 sec (10 sec is recommended to be sure).

Still no luck with ESCD reset 😭.

PARKE wrote on 2021-01-28, 12:53:

Some ASUS boards of that generation do not have a jumper but they do have two solder pads marked [CLRTC] wich stands for 'clear […]
Show full quote

lazaj30 wrote on 2021-01-28, 12:03:

Asus P2B rev.1.12 doesn't have clr CMOS jumper so I unplug it and remove the coin cell for 1 hour.

Some ASUS boards of that generation do not have a jumper but they do have two solder pads marked [CLRTC] wich stands for 'clear real time clock'.
According to the manual of my P2B-S you should:
-turn off the computer and unplug the AC power
-short the two solder points labeled CLRTC
asus_p2b112cmos2.jpg

You're right, I have missed it !

I've made some progress, I've got an Adaptec aha-2940 UW in this PC, if I remove this PCI card and disable fdc in bios the motherboard boot correctly.
With the aha-2940 UW and fdc disable in bios, the motherboard hang on PNP init ...
So maybe something with the aha-2940 UW ?

PS : aha-2940 UW bios version 2.20 (latest)

An another update ...
I have found this article : https://storage.microsemi.com/en-us/support/s … mpatibility.htm
The aha-2940 UW was plugged in PCI port 3. I plug it in PCI port 4 and tada ! Problem solved !
Now it's time to try to use the aha-1542b fdc controller.