Non-working floppy disk drive

[adlerhn]

I recently got an Atari 1040 STFM, but unfortunately the floppy disk drive doesn't work.

When I boot the computer with a disk inside, it does exactly the same sound as if there were no disk inside at all. The orange light is on, it makes some faint noise, and after 40 seconds it boots to GEM.

I have tried to clean the headers, but the drive won't even attempt to read the cleaning disk.

I have read around that some old floppy disk drives can be fixed by replacing some capacitors or a rubber band. From the symptoms above, any idea of what it may sound like? I'd definitely not want to buy a non-Atari floppy disk and have to drill the case.

[Zogging Hell]

If the platter is spinning you will hear whirring sound when a disk is inserted, the head moving back and forth makes a 'grinding' (for want of a better way of describing it). If you don't hear one or the other of those then it might narrow down your problem.

I'd take the top off the ST and remove the screws from the base of the drive (the big long ones) so you can lift it up and look underneath. You will have to remove a small bit of shielding over the floppy drive as well; leave the rest on so you don't accidently touch the power supply when the computer is on. Some floppy drives you can see the platter mechanism turning when you insert a floppy (with ST on and press the reset). Others you might have to remove a bit of the shielding round it. If it doesn't spin then Gadgets capacitor fix might work. If the drive spins then it might be the head has stuck. Remove the drives shielding and look for the arm that extends over the disk platter/ disk. With the ST on insert a disk and see if the head moves back and forth (it might only do this briefly, depending on what is on the disk). If it doesn't move then try spraying some lubricant into the gearing that controls the head (with the ST off of course) and manually try and un stick it by gently moving the head back and forth on its runners.

Unless your ST is quite and old one with the big button floppy drive it is unlikely to be the drive belt problem. If it is you will need to dismantle the drive. The belt which usually turns the platters slowly rots and can be replaced by the ones being sold on ebay.

[adlerhn]

Thanks a lot for your thorough response. I will try to follow your advice as far as I can.

For the time being I've tested the computer with a different floppy disk drive, and it works, so the DMAs and that are fine; the issue is just in the floppy disk drive.

[Robson]

I've just had a drive fixed by changing the caps. When the machine booted the head moved once (one little flicker) but that's all. I've changed the 2 caps on the pcb (one near the motor and the other one around the power connector I think) and now works fine.
You can check if you strip the drive down and connect to the st (make sure it's not sorting anything) and see what's happening when switching on.

[catmando]

I've just had a drive fixed by changing the caps. When the machine booted the head moved once (one little flicker) but that's all. I've changed the 2 caps on the pcb (one near the motor and the other one around the power connector I think) and now works fine.
You can check if you strip the drive down and connect to the st (make sure it's not sorting anything) and see what's happening when switching on.

Are you sure it was the new caps that fixed it?

I have floppy drives that show a small amount of head movement when the power gets switched on and they perform fine.

[Robson]

Either this or the Tooth fairy.
I didn't do anything else after cleaning it but replacing the caps.
It is normal to have movement at boot what's not is not trying to read after with disk in drive.
Just wanted to share this experience with you. Caps from China are cheap and not hard to replace.

[catmando]

Either this or the Tooth fairy.
I didn't do anything else after cleaning it but replacing the caps.
It is normal to have movement at boot what's not is not trying to read after with disk in drive.
Just wanted to share this experience with you. Caps from China are cheap and not hard to replace.

In the refurb process did you unplug/replug any of the ultrathin ribbon cables that often appear on these drives?

[Robson]

Nope. Really just gave it a good clean...that did not sort it. Then replaced the 2 smd caps and works since then so in my case these actions worked.

[adlerhn]

Finally I got around to open the lid on top of the floppy disk.

The platter does not spin: there is no noise from it at all, and I can see that the floppy disk I have used is definitely not spinning (the disk has a speck of dust that I can see).

The head makes a faint movement, like a shake, every 2-3 seconds, but does not come close to the disk. On the other hand, if I manually move the head towards the disk and turn the computer on, the head will successfully move to its default position, and keep shaking every 2-3 seconds.

So, it looks like the overall issue is that the platter does not spin, for which I can try to switch the capacitors, right? I haven't soldered anything in years, but this doesn't seem too difficult. Is there a step to step guide somewhere?

The drive is an EPSON SMD-480L, like this one: https://www.youtube.com/watch?v=X_JCWWHKXIc

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[Zogging Hell]

The head will probably move like that if the disk isn't spinning so that sounds about right.

There are probably a fair few guides on Youtube for desoldering capacitors from a PC motherboard, and I imagine a floppy disk drive of this vintage will probably be a lot less easy to damage and as it is not working there is not much to loose if you cock it up. If you apply heat to each leg in turn and gently pull on each you will be able to get the capacitors out fairly easily. Then use a solder pump to suck out the solder in the holes. Just be careful not to apply heat for too long. Stick new capacitor in and resolder. Good luck!

[adlerhn]

Thanks! I bought the 10uF capacitor the other day, but I am actually having trouble finding the 56uF one in my city; I'll keep searching around.

[1024MAK]

56uF is not a common value. Assuming it is not used for any timing function (unlikely), try using either a 100uF or a 47uF. Also use low ESR types.

Mark

[adlerhn]

I finally replaced the capacitors. Unfortunately, the drive still doesn't spin

[adlerhn]

I have fully disassembled the drive and found a third capacitor in the board where the motor is. Will try to replace it and see if the motor moves then (if I can find a replacement cap, 10uF 25V).

[catmando]

Here's the video I used to get the platter working on mine

[adlerhn]

I have replaced the 3 capacitors, and there is no difference whatsoever. I think it is time for me to desist.

@catmando: thanks for the video. I have replaced the capacitor that you indicate, but the drive still doesn't spin.

Also, I have another (much newer) non-working drive where the motor does spin, but in a strange way (maybe in a more silent way?). However, it doesn't read anything and after about 10 seconds it just stops loading/spinning and goes to GEM (tried with tested games). I have replaced the 2 capacitors in that one and cleaned the headers, but no luck.

Time to buy a couple of PC floppy disk drives and mod the cases as required.

[Zogging Hell]

Is the newer drive an Atari one? If not check the drive id on the much newer drive, it's may well be set to be on the PC (id 1 iirc), whereas the ST wants it to be id 0 (I may have got that backwards). If the id is wrong you will end up with all sorts of weird behaviours. The id is either swapped with a jumper (if you are lucky), a solder pad (more tricky - and sometimes tricky to find) or may not even have an easily identifiable way to change the id at all (worst case scenario). If it is an Atari one, the heads could be out of alignment or despite the cleaning it may still be dirty. How did you clean the heads? Isopropyl and a cotton bud?

[adlerhn]

Hi, yes, the newer drive is also an Atari one, from a different computer. I cleaned the heads using a dry floppy disk cleaner disk, exactly like this one: http://amigakit.leamancomputing.com/cat ... leaner.jpg

[Zogging Hell]

Might want to try some isopropyl alcohol on a cotton bud and clean the heads manually, or on a floppy disk cleaner you can put a couple of drops of isopropyl on (like the one Amigakit have in their 3.5" Floppy Disk + CD/DVD Cleaning Kit).

I found when cleaning it was worth trying to format a floppy afterwards as this usually made it easy to see if further cleaning was required (the format starts to work then you hit a problem then repeat clean and try again). It also seems to be quite good for shifting any gunk if combined with cleaning (although I would use a floppy you don't mind loosing). If formatting works without a hitch and you can read/ write that disk but you still can't read other disks then it is probably the heads being out of alignment.

[dlfrsilver]

yes cleaning the heads with IPA and cotton bud are the way to go, and also clean the motor cog rail for the dirt, and grease it again with vaseline oil (specific for micro-mecanisms).

[Miguel]

I just repaired a Epson SMD-480L and thought I would share a little info here. The top board has a 56uf 16v cap and a 10uf 16v cap and there is another one of the same type (a 10uf 16v cap) on the bottom board. To gain access to the bottom board you must remove the bezel so you can remove the sleds by pulling them toward the front of the drive, this also requires the removal of 3 small springs. Now I left the circuit board attached which meant I had to swear a little bit while poking my soldering iron around a screw tab and it should be noted that the 10uf 16v cap on the bottom board is quite small so as not to interfere with the mechanism above so if you do use a bigger one like I did you kind of have to angle it diagonally so it sits flat.