X68000 Compact Floppy drive repair...

[BlueBMW]

I seem to be having no luck getting some of these compact floppy drives to work.  I've got 16 floppy drives here and cant get but maybe one of them to read disks.  I've tried recapping, regreasing, cleaning drive heads, different machines, different flat cables, no luck.  Is anyone really good at fixing these drives and can you offer any suggestions?

Typical issues I'm having are...
Power light on drive flashing on and off
insert disk, spits it back out right away.
CRC errors

[doubleflash]

The Drives are little bit sensitive against emissions, so test it inside your tower with the shielding metal plate on.

[caius]

I seem to be having no luck getting some of these compact floppy drives to work.  I've got 16 floppy drives here and cant get but maybe one of them to read disks.  I've tried recapping, regreasing, cleaning drive heads, different machines, different flat cables, no luck.  Is anyone really good at fixing these drives and can you offer any suggestions?

Typical issues I'm having are...
Power light on drive flashing on and off
insert disk, spits it back out right away.
CRC errors

Here the same, BlueBMW, it seems you can break them by only opening them....Have you tried heads alignement?You can do it using games like Motos or Scorpius, especially this last will test how good the alignment is at the beginning and end of the disk.Then check also all cables inside, both the flat ones (especially the small one which come from the heads) and the colored ones with the small connectors from the motor to the PCB
IMHO I'd suspect also some faulty ICs on the motherboard (the main controller especially) or some bad traces.Anyway , they are fragile like crystal...
Does the eject works on all units?

[BlueBMW]

Seems like eject works on all the units that power up properly.  I pulled all the drives out of all the compacts I have here (7 total) and it looks like I have 4 good drives total lol.  That leaves about 22 drives of which I know 16 need work / help, the other 6 or so I havent tested yet, though they're partially disassembled and have had the caps removed but not replaced (not by me)

Any tips on head alignment?

[caius]

These tips about floppy heads alignement are courtesy of Eidis (I hope you are fine and, please, don't work too much.. )


"There should be two screws holding the upper head to the assembly. Loosen both of them, but leave one slightly tensed, just enough to be able to move the upper head to the left and right, using gentle force. I prefer to keep the right screw slightly tensed. The trick here is to find exact horizontal and vertical alignment of the upper head. You will know that you have something going on when the drive starts booting from disc. If I recall correctly, both drives need to be connected in order for X68000 to boot from them. Some great games for floppy calibration are Motos and Scorpius. Start with Motos, because it is more forgiving. Then move on to Scorpius as it will test how good the alignment is at the beginning and end of the disk. I have noticed that a good start is to position the magnetic stripe of upper head exactly over the one of lower head. Then try moving the upper head by tiny bits to the left, then try reading a disk. If that does not work, a little more to the left and so on and then to the right. If that does not work, try moving the head slightly up or down and repeat the procedure with left and right. Do it while the floppy disk is in the floppy drive. It will make things a lot easier but be gentle  Eject and reinsert floppy after every adjustment"

[eidis]

 BlueBMW,

Another thing to try would be cleaning heads with medical grade spiritus. I had one PC floppy drive which was faulty and cleaning heads with ordinary tap water did not help so I used 96% medical grade spiritus (isopropyl alcohol ?) and once some really hardened goo from upper head was gone, the drive started working like a charm. If you don't feel too comfortable about using 96%, start at 50%, otherwise it will not be effective against extremely hardened dirt.

IMHO the best solution before you start the head alignment would be cleaning the upper and lower head with a q-tip and 96% medical grade spiritus. Do not use force, just press the q-tip enough for the dirt to come off. Use another q-tip after that to clean off the residue. Then clean the heads once again with a q-tip and tap water so the highly concentrated spiritus will get dissolved. Finish by wiping off the water with another q-tip.

Now a little more info about the drives themselves. Most of the times the magnetic stripe of upper head is attached to the upper head mechanism with something similar to a very robust scotch tape. It loses its tension with time and so the upper head gets dis-aligned. There is a track 0 sensor on the drive as well which tells it when heads have returned to track 0 and aligning it could help.

The procedure is a royal pain in the ass, but here are some guidelines which could come in handy:

1) Format two floppies with a confirmed good drive and write Motos and Scorpius to them.
    a) Motos is more suited for testing track 0 sensor and initial testing of head alignment
    b) Scorpius is awesome because it does a lot of seeking to all regions of floppy disk. For simplicity's sake I will use the terms begining (start - middle of the disk), middle (middle - 75% of the disk) and end of the disk (75% - end)

2) Follow Caius instructions and start with Motos. Insert the floppy disk and reset the X68000. It should start spinning the floppy disc. At that point start aligning the upper head. The trick here is to find a sweet spot when the drive starts reading the disk. Once you have found it, it will move the heads to the next tract. The floppy disk should spin for a long time so you will have plenty of time for trial and error. Eject and reinsert floppy disc upon every reboot to avoid false positives If possible, do not touch the track 0 sensor because it could cause troubles for multi floppy games. The most common fault is that a drive with misaligned track 0 sensor boots fine from the first floppy disc but does not see others when the game prompts to insert them. IMHO Etowaru Purinsesu was one of them, but I'm not 100% sure. Try testing it with games which do not show contents of the disc when trying to list the directory.

3) After you have successfully booted Motos upon every reboot, move on to Scorpius. The most common fault at this stage could be disc not reading after track 40. You will probably know by now how to tell by sound if a drive is returning to track 0 in normal operation or if there is a read error. By default the drive tries to reread a bad sector by returning heads to track 0 and then to the affected sector for three or more times and only then X68000 spits out disk error message. Once again you will have to search for a sweet spot so Scorpius will boot and load without hiccups and returning to track 0 because of a read error or trying to reread a sector.

4) The following things should be considered when aligning a drive. Bad 100uf capacitors always spell trouble. Replace all capacitors on the drive, if possible. It could eliminate the need for drive alignment. Bad rotating disc assembly spells trouble as well. If you hear ye good 'ol screeching sound of worn bearings, the floppy disc will still be read by the drive, but the precision will suffer because of the misaligned RPM of the drive.

Best of luck and keep us posted !
Eidis

P.S. Thank you Caius for moral support. The promise is not forgotten, it will only take more time to accomplish it

[BlueBMW]

Wow, thanks for all the great information!  Looks like I have my work cut out for me!

[Maxwar]

For now my compact FDD are working good, i dont want to dwell on the possibility of them failing... I was actually thinking about that today :/

I have many PC floppy drives that are working very bad or not at all ( about 20 )  and cleaning them will not bring them back.
Head alignment is the last step but it is so tedious.
I know some people do it with help of an oscilloscope somehow but there also exists special disk kits for PC floppy drives that are designed to realign heads too. 
Interesting to learn such tools for the X68k are included in games! But maybe there is a dedicated disk kit somewhere?

[eidis]

Maxvar,

Head alignment for PC drives is very easy and it can be done in ~10 minutes without any fancy gadgets and kits. There is a program called Floppy Disk Reanimator.

Get it here:
http://old-dos.ru/files/file_245.html

The program must be run from pure DOS. It graphically shows in real time which sectors are good and which are bad. Take two floppy disks and format one with a confirmed good drive to 720kb and the other to 1.44mb. Run Floppy Disk Reanimator, insert 720kb formatted floppy disk and do a search for defective sectors and proceed with the head alignment. Once you get it to read entire floppy disk without hiccups and errors for at least two times in a row, insert 1.44mb do fine tuning if necessary.

Is there anyone who knows or could write a similar program for the X68000 ? I had high hopes for FileMaster but unfortunately it is not suitable for this task. The program could run in plain high-res text mode and display the info of tracks as "O" for good sector "X" for bad sector. Please let me know if anyone is willing to donate their time and knowledge for the cause.

Keep the scene alive !
Eidis

[gypsie]

It's an old topic but i need to ask something about compact floppy drives.

I ve 2 floppy drives with no "power on" ( no light ). I ve tested them on a good x68k compact so i know that the drives are faulty and nothing else.

Do you think that replacing caps could revive the drives?

Thank

[eidis]

Hi Gypsie !

I'd say the odds are 50/50.

Keep the scene alive !
Eidis

[gypsie]

And if the caps are changed and my drive is always powered off, is there something else to check?

[caius]

And if the caps are changed and my drive is always powered off, is there something else to check?

Check the flat cables,  +5V is routed  from motherboard  through these .Then check also diodes , voltage regulators (if any) on the  FDD PCB.Personally I gave up to repair them and installed an  HxC SD floppy emulator on my CompactXVI, it works pretty well.

[eidis]

 Hi Caius !

Any chance of writing a tutorial on HxC mod ?

Keep the scene alive !
Eidis

[famiac]

Hi guys, i have a similar problem and i want to try head realignment but i don't really know where to start. Could someone point the screws out to me?

imgur.com/t0vICFH

I loosened the top screw to align the heads.. I'm not sure if it's the screw i'm supposed to be using.
If i put slight pressure on the upper drive head, it reads properly! This drive can be resurrected, i just don't know what it needs!

Video added:
http://youtu.be/l0B9YB1_TP0

[eidis]

 Hi Famiac !

Pay close attention to the pin which goes from the spring to the drive head. Usually there are three notches which allow selecting the desired tension. Try moving the pin to adjecent notches and see what happens.

Keep the scene alive !
Eidis

[famiac]

Hi eidis! Moving the pin did not alter the behavior. Where are the two screws for the drive head?

Update:
Got it working! I just twisted the upper drivehead counter-clockwise because i noticed it was a little off and then it started working.
I get some CRC errors sometimes but if i hit the 'R' key, it always works. And scorpius boots just fine. Am i good to close this thing up?

[eidis]

 Hi Famiac !

Test it for a couple of days and only then reassemble your X68000.

Keep the scene alive !
Eidis

[famiac]

Alright. I'll test it again in a week. If it still works, i'll close it up.

[leonk]

let's bring this from the dead ..

I got an idea. Why not come up with an adapter that will allow x68k fd to work in a PC?? then use PC software to align head?? Will that work or is drive just too different to be used in a pc with custom adapter?

[kamiboy]

I wrote an X68000 tool to help with head alignment a while back. I think I called it FDR68k, try searching for it as I remember posting here back in the day. Of course you need a way to load the program on your machine...

[famiac]

Does it work for the 5.25" drives too?

Precise information on floppy drive alignment seems to be really elusive

[kamiboy]

It should work for 5.25" drives as well, it uses IOCTS calls to verify clusters, those are not drive type specific. As for alignment, I think a proper cleaning of the heads is advisable before attempting anything else.