A4000D Floppy Drive Issues

[DanielAllsopp]

I'm having some issues with my A4000; both the internal HD drive and the external CUAMA drive that's attached to it. Only a month ago the external drive would read and write to floppy disks no problem. The internal drive has always been iffy.

There's also an intermittent issue with the keyboard when I first switch on; the caps lock flashes alternate between 1 flash and 4 flashes depending on its mood.

So, I've switched the A4000 on tonight and it won't read a single disk through that external drive. They write and verify fine through the Greazeweasel on my Mac.

I'm running 'Amiga Test Kit' and the CIA timing tests all come back fine. The floppy tests say there isn't a READY signal, and suggests it's an ESCOM drive.

I'd try and diagnose it myself but there's no documentation for the 'Amiga Test Kit' software so I'm a bit lost.

Any help would be greatly appreciated! Thanks.

[Kin Hell]

Try cleaning the Internal Floppy drive switches with switch cleaner. Gently, bounce them up & down repeatedly with a flat bladed screwdriver.

DF0 screwing up can have issues with other drives functioning correctly.

Floppy drives of this age need more TLC than ever.

DF0 being High Density will have a pair of switches each side of the Floppy slot on the front edge. The external Cuama will only have one pair of switches opposite side to the eject button.

[DanielAllsopp]

Originally Posted by Kin Hell

Try cleaning the Internal Floppy drive switches with switch cleaner. Gently, bounce them up & down repeatedly with a flat bladed screwdriver.

DF0 screwing up can have issues with other drives functioning correctly.

Floppy drives of this age need more TLC than ever.

DF0 being High Density will have a pair of switches each side of the Floppy slot on the front edge. The external Cuama will only have one pair of switches opposite side to the eject button.

Thank you, will take a look at this today!

[DanielAllsopp]

Originally Posted by Boing-Ball

You haven’t mentioned if your A4K has been recapped or that you have removed the ticking time bomb of the VARTA battery on the motherboard.

Sorry, I should have mentioned that it’s been fully recapped and the battery was removed probably 20 years ago now and replaced with a lithium coin battery.

It doesn’t have its original PSU though, it’s connected up to an ATX supply with an adapter.

[hooverphonique]

Some of the signals from floppy to computer (e.g. READY) go through the same cia chip (U350) as the keyboard signals, so maybe your problem is there.

[giantclam]

Originally Posted by hooverphonique

Some of the signals from floppy to computer (e.g. READY) go through the same cia chip (U350) as the keyboard signals, so maybe your problem is there.

Yeah...now we can presume power is OK, a hinky CIA chip would explain it ~ same old story, swap CIA chips in sockets, retest and see if fault follows the chip...

[DanielAllsopp]

Originally Posted by giantclam

Yeah...now we can presume power is OK, a hinky CIA chip would explain it ~ same old story, swap CIA chips in sockets, retest and see if fault follows the chip...

They're not socketed on an A4000 are they? I'll open it up later and see what's what.

[giantclam]

Originally Posted by DanielAllsopp

They're not socketed on an A4000 are they? I'll open it up later and see what's what.

..my bad, no they're not (they damn well should've been imho =)

[Kin Hell]

Originally Posted by giantclam

..my bad, no they're not (they damn well should've been imho =)

Back in the day, Commodore were trying to get rid of Sockets for increased reliability whilst also making savings on manufacturing costs.

To save blowing CIA Chips, rule of thumb is don't plug anything in or out whilst the miggy is powered up. IE, joystick/mouse, serial, parallel ports.
Golden Rule is don't plug or unplug anything. Some folk even think it's okay to Hot Swap CF devices. - It isn't.

[DanielAllsopp]

How much faith should I put into this 'Amiga Test Kit' software? It says all of the CIA timings etc are good. Thing is, there's no documentation at all for it so I'm just going in blind.

I will try and clean those switches on the floppy drives this weekend though, see what happens there.

[DanielAllsopp]

TD/DR; something went bang!

So, after a couple of weeks:

- testing
- different existing cables
- new cables
- swapping between A4000 and A1200
- jumper settings
- external drive tests
- IPA cleaning
- Amiga Test Kit
- XCopyPro

I thought I'd cracked it... slowly following the guide here to re-align the drive heads: Amiga Floppy Disk Drive Track Alignment.

Symptoms where the drive would format, read and write to a disk that was formatted on the machine itself using that drive. Put it into a different drive though and it was completely knackered and unreadable.

Writing a disk with the Greaseweazel; that disk worked on the A1200, but not the A4000. So I opened up the A4000's internal drive, cleaned literally 30 years of dust, fluff and hairs out of it, hooked it up and ran Amiga Test Kit head alignment. I slowly adjusted the head alignment daughterboard until all of the sectors were "OK", and then onto the next track. Slow work!

Everything worked! So, the CIA chips were fine, the drive itself was now fine after being cleaned etc. I managed to boot from the Greaseweazel disks, I played Aladdin and Alien Breed 2! Marvellous, and so time to put it back together.

That I did, and as soon as I turned it back on to double check it was still working, I got a little puff of black smoke from near the drive heads and a nasty burning smell filled the air. The drive itself still worked mechanically, but now the lower side on all disk reads comes back as reading 'X'.

I'm assuming now there's nothing that can be done for the drive so it's sitting unconnected in its bay, never to work again! I now have the internals of a CUMANA external disk drive configured as my new DF0 in the A4000 (it wouldn't work externally for some reason) with a ribbon cable and power lead hanging out of the back of my Amiga because it wouldn't fit under the original drive.

It's in a right sorry mess but at least I can continue testing. One day I'll get around to making it look nice again!

[Screechstar]

Really sorry to hear that - especially after all the time and effort with testing and the work to get it sorted!

Any indication of what went pop and (sorry... standard question...) were all the power and drive cables installed the correct way around?
I've made that mistake myself... had a different computer with an IDE unit I somehow installed one pair of pins across from where it should and managed to get away with it that time... I was lucky!

[DanielAllsopp]

Yeah, it's a pain in the arse alright! I assume it's something to do with the bottom drive head as it's not returning any good sectors now, they're all bad. Maybe I did connect something up wrong this time, but I've done it literally dozens of times lately and it's been fine, but still a possibility.

Sods law eh?

[Kin Hell]

It's a proper bummer once the magic smoke escapes isn't it!

How unfortunate for you.