Jackhead wrote on 2023-03-03, 17:08:

Any suggestion? Do i have to adjust the arm?

Don't touch any of the arm or stepper motor screws unless you know how to re-align the drive afterwards. Does the head move at all? If you have BIOS option seek drives on boot that's the easiest way to tell, otherwise install IMD and use aligment function to test it. If there is no movement try rotating the wheel on the motor - on unpowered drive and with fingers, it should rotate (and move heads) quite easily. If it does move then perhaps the track 0 sensor is fouled up, move the head to the center and you should have some access for the nozzle of can of air to try and blow it clean.

I load IMD and try some tests. The head is moving. I cant see there is any mechanical problem at all.
In IMD when i try to format or erease the disk it gives me error " no interrupt from FDC "
My controller is a QD6580W.

It's a VLB card? Try non-VLB (standard ISA) controller, and if you have 40MHz system (or 50 or overclocked) reduce the clock to 33MHz and try again. And try to re-seat the card as well, I'm not sure if FDC uses any of the 32-bit signals but in general the VLB connectors are not all that reliable - especially after many insertion cycles or if dust got into them.

It is. I got now another I/O Controller a DTC-2278D to crosstest. But the same Problem with drive B: .
My system is running with 33MHz (486DX2/66).
Drive A: is working normal on the bus. I also have the driver for the IDE chain installed, PIO4 with around 6MB/s working fine.

I bought this drive as "working /tested" well that has nothing to mean, but i like to understand what the problem is.
I never had a 5.25 drive before so im not sure at all..

Wait, I got lost a bit. So you have 2 drives? On the same cable, on the same controller? And the one set to A: works just fine but the B: ones does not? And you get the head to move in IMD but not otherwise?

You'll need to provide some more info: Is that drive actually jumpered correctly? What cable are you using? Did you try swapping the A: and B: drives around? Is IMD able to measure drive RPMs (there's a test for that) and what does it show in alignment test (does it detect sector data at all or just shows ? instead).

omg im so stupid ok, i see the jumper now. It was on ID:0 so ok i jumperwd it on 1 . So now i can run all the tests on IMD and pass it.

When i now insert a floppy and want to switch i gor the message "drive not ready"

Yes i have two drives a 3,5 and this 5.25 on one cable . the 5.25 is before the twist, the 3.5 after the twist.

edit: ok jumped it also to DC now its working fine 😀