DeChief wrote:

I've been told that this system uses a proprietary floppy drive controller and that I can't replace the drive with any old regular one, so my question is this:

You can replace it with a decent subset of floppy drives, I would think.
The main difference is that your floppy drive needs to have a 'motor on on drive select' capability, since the controller does not send a separate 'motor on' signal.
So you'd see the led coming on when the drive is accessed, but the motor won't spin.
You could probably modify any drive by just jumpering the drive select and motor on pins.

Second thing is that it doesn't use the 'twisted cable' trick where all drives are configured as drive B, and the twist makes the drive after the twist effectively drive A.
So you need to be able to jumper the drive to A.

DeChief wrote:

If I get an IBM PC/XT floppy drive ISA card, would it work in this machine? Is there anything I should be careful of?

Probably won't work, because I don't think you can disable the onboard floppy controller. In which case they'd be conflicting.

Try changing cable. Mine didn't do anything when I got it, then i found out that the cable is dead and now it works.

Scali wrote:

You can replace it with a decent subset of floppy drives, I would think. The main difference is that your floppy drive needs to […]
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DeChief wrote:

I've been told that this system uses a proprietary floppy drive controller and that I can't replace the drive with any old regular one, so my question is this:

You can replace it with a decent subset of floppy drives, I would think.
The main difference is that your floppy drive needs to have a 'motor on on drive select' capability, since the controller does not send a separate 'motor on' signal.
So you'd see the led coming on when the drive is accessed, but the motor won't spin.
You could probably modify any drive by just jumpering the drive select and motor on pins.

Second thing is that it doesn't use the 'twisted cable' trick where all drives are configured as drive B, and the twist makes the drive after the twist effectively drive A.
So you need to be able to jumper the drive to A.

DeChief wrote:

If I get an IBM PC/XT floppy drive ISA card, would it work in this machine? Is there anything I should be careful of?

Probably won't work, because I don't think you can disable the onboard floppy controller. In which case they'd be conflicting.

Sounds good. Got any recommendations for reliable and cheap-ish drives? Living in Australia makes shipping expensive from overseas, and not many drives show up here.

krivulak wrote:

Try changing cable. Mine didn't do anything when I got it, then i found out that the cable is dead and now it works.

Since the drive still spins I doubt this is the problem, but I'll try it anyway.

krivulak wrote:

Try changing cable. Mine didn't do anything when I got it, then i found out that the cable is dead and now it works.

Tried it just then, didn't work. 😢

Then you have to find Amiga floppy drive somewhere...

krivulak wrote:

Then you have to find Amiga floppy drive somewhere...

Oh, are Amiga floppy drives compatible?

DeChief wrote:

Oh, are Amiga floppy drives compatible?

Probably.
In general Commodore mostly used Chinon drives.

Yeah, I believe they were since I tried to use this drive in PC and it didn't work. My idea is that Amiga drives should work since Amiga and Commodore is the same company - Amiga is successor.

krivulak wrote:

Yeah, I believe they were since I tried to use this drive in PC and it didn't work. My idea is that Amiga drives should work since Amiga and Commodore is the same company - Amiga is successor.

Amiga drives have some signals reversed. They may or may not be compatible with the PC20-II without modifications. I'm not entirely sure.