PC Floppy to Amiga convert for A3000?

[melange]

Okay, this being my first post I hope I don't come across as a complete loon.

Approximately 7 years ago I was given the insides of an A3000 desktop, one with the roms that load images from the HDD.  I had no case to put it into and already had an A1200 030/50 and an A500 as well as a CD32 with SX-1 expansion, so I wasn't really worried about not being able to use it and packed it away waiting for a case to come my way and the inclination to build it up.  Having recenty aquired a case I decided to have a bit of fun with Amigas again and get to work.

I have now almost completed building it into a case and recognised that the A3000 floppy drives are too chunky to fit into the case, so naturally I have begun experimenting with PC floppys in an effort to make it look a little better.  Initially I couldn't get the PC drives to work at all, then after some fiddling with the DS0/DS1 drive assignments on the floppys PCB I got some action, but only when the OS made a call to the drives.  They were not recognising DiskChange events.  After much scouring of forums and technical notes on the net I tried a hack of shorting pin 2 on the floppy drive itself to pin 34.  Things improved at that point giving me two drives that would load a disk when inserted, but external floppy drives no longer functioned.  I then decided that a better solution would be to hack an old PC floppy cable to suit the Amiga standard internal cable (twist at the second connector at the end of the cable on pins 4,5&6) as well as sending pin 2 to 34 and 34 to 2 respectively at the motherboard end of the cable.  This improved things again giving access to both internal and external floppy drives.

At this point I was thinking I had solved the problem completely, until I tried some tests using diskcopy programs like Powercopy and Xcopy.  Both programs recognise the drives exist but insist that there is no disk in the drives.  However Dopus is quite happy to perform a copy of disks from/to any drive internal or external.

Is anybody aware of what signal might not be finding it's way back to the Amiga?  I am close to solving this (I think) but have run out of ideas currently.

The drives are quite old, matching 1.44mb Sony units.
The mobo had some battery damage but with the original floppy drives it worked fine.

Any ideas greatly appreciated

Cheers

[melange]

Firstly thanks for the rapid response folks.

I have a Teac FD-235HF which I just wacked in for a shot, same result.  Still mucking about ATM :-)

Thinking I may have to pull out the cable I made and do a continuity check to make sure i got it right.

[melange]

Hi GiZz72,

Thanks for another idea, tried it with DD disks, same thing.  Must be missing something obvious.  Will have to stop for a few hours and go to teach my class of PC heads .  Looks like yet another late night coming up.  Thanks for all your help.

Keep you posted on my epic experience as it unfolds.

[melange]

Ok, I think I have solved this little problem.

After much reading of pinouts on both the Amiga and PC side of things, I stumbled across my A500 manual and viewed the pinouts for the external disk connector.  It states that the "Disk Ready" signal is "Active Low".  So I thought I'd force it low by pulling it to ground.  To test this I shorted pin 1 (Disk Ready) of the external disk connector on the A3000 to pin 3 (ground) with a paper clip.  I then booted up and both drives still worked and they worked in Xcopy/Powercopy.  Looked good at that stage, however I had two Icons on the workbench that claimed there was a DF2: and DF3: connected, with question marks against them.  This was ugly to say the least, so I pulled out the internal drive plugged in at the end of the cable (after the twist) and shorted pin2 (disk ready) to pin1 (ground) on the drive itself.

Now I have 2 working internal Sony High Density floppy drives (functioning only as DD), with 2 regular Double Density external Amiga drives all functioning very nicely, as far as I can tell.

Just to make it all clear for anyone who's interested...

I took an old PC Floppy cable with connectors for an A: and B: drive and removed the connector at the motherboard end of the cable.  I then swapped pin 2 with Pin 34 and re-attached the connector.
I removed the connector at the A: drive end of the cable (the one with the twist) and changed it so the twist was like my original internal cable (twist at pins 4, 5 an 6) and re-attached the connector..
Finally I shorted Pin 1 and 2 on the 34pin connector on the drives PCB (soldering required). This would probably also work if you did it to the cable itself, was just easier to do it to the drive.
The only other requirement I can think of is to set one of the drives to DS0 and the other to DS1.  Really don't seem to matter which one as far as I can tell, although you will find lots of conflicting info with regards to this on the net if your looking for answers.  In the end I had to make my own answers.

If I find any problems I will post again with whatever they are.

Hope this of help to someone oneday.


  :-D

[melange]

Yes appears to be a very cool place indeed .  Had I known about it earlier I would have jumped onboard then.

Looks like they work OK, have noticed one thing already however as pointed out by gizz72 earlier on, the drives being high density react to HD disks differently.  Now to see if I can make them appear DD no matter which type is inserted.

Also have to wire the reset switch on the Tower to the CPU reset line and extend the Keyboard and Mouse/joystick ports to the rear of the case.  More fun ahead  :-D

Back with more soon...

[melange]

Hmmm,

Yep I'll do that, not that fancy to look at ATM I'm afraid, the case is silver and the drives are white of course, but it's working :-)

On the upside it hasn't cost me cent so far :-)

Just fixed the DD/HD problem, wired across the switch on the floppys and now all disks are DD as far as it's concerned.

  :-D

[melange]

Damn, I didn't solve it.

I did all my testing with 4 floppy drives plugged in and it works fine.  However, when i disconnect the 2 external floppys, I get the good old DF2:? and DF3:? icons appear on my workbench.

I just tried another hack involving the use of some diodes to create the ready signal.  This also works and the Icons are no longer present.  Xcopy thinks all is fine.  Powercopy, which has some extra ciruitry in the form of a dongle between drives, insists on doing a drive speed check, which it never had to do before.  So I'm still not there yet.  However the use of diodes opens more possibilities I didn't have before.  I'm off to by a handful of diodes, the correct type, the ones I used possibly were not.

As for the tower, some creative wiring and metalwork still ahead.  8-)