Any idea how to resurrect floppy drives?

[Mk.558]

Just got done finishing up the last bit of work on my SE/30, and did the floppy drive a favor by:

1) Degreaser on Q-tips, very carefully cleaning only the areas where mechanical action takes place.

2) Regrease lightly said spots.

3) Dry Q-tip on the drive heads.

Now it doesn't work any more. The first drive I had with this machine I was far more elaborate, spraying down the entire assembly with degreaser and blowing it dry, then making sure it was dry before use. That failed to work (although I don't know if it was working before the clean or not, it had a bad MB).

Took it back apart, ran straight degreaser on the heads to get them wicked clean. Still doesn't work. Yet I do not much more than the cleaner disks do -- how could it fail?

Experiences?

 

[phreakout]

Which drive are you referring to? Is it the one I sent you or the one you had internally mounted, before you received mine?

Sometimes drives are hit and miss; it could be alignment issues or the heads could need degaussing (Several years of use, plus buildup up iron oxide, plus magnetic flux buildup can cause that; no different to demagnetizing reel-to-reel tape recorders.). Another possibility could be the RP10 (network filter). You could try taking it out of circuit to see if it cures the internal drive read/write issues. Just remember that if you remove the RP10, the external floppy drive port becomes disabled, until you return the part back in the circuit.

Btw, still plugging away at the HDD as promised. Will get it to you asap.

73s de Phreakout. :rambo:

 

[Mk.558]

It's an internal one that came from another SE/30 I got off eBay because I thought the one I had had a fried SCSI chip, when in fact all the drives I had were fried instead.

I'm not sure how cleaning a floppy drive head with a dry q-tip gently destroys it. I tried formatting disks, it gets about 3/4 the way through then *euunk eeeunnnk* and rejects the floppy as defective. No trusted floppies mount or read.

 

[techknight]

Mis-Alignment for sure.

Only way to align these, is on a test bench. You must have a test disk, or a disk with physically/mentally known magnetic patterns, and you must force the drive spindle motor to ON.

Take an oscilloscope and hook to the head assembly.

Then move the head on track 0, and turn the stepper motor itself physically until the scope shots are at thier maximum peak. The drive is aligned.

Stepper motors move so many degrees per step. CANNOT move anywhere in between. If the head looses "alignment" it will land "in-between" during steps. you must physically turn the motor while watching the heads from an oscilloscope using a known good test disk.

thats track alignment.

Disk-to-head tension alignment i havent figured out yet, this will cause weak pickup as well as track mis-alignment. Think of cassette tapes here. same principals apply.

The reason this cause disk rejection errors, is because when the drive goes to record, it writes the data on the tracks which are now "misaligned" from the REAL track positions. So it doesnt fully "erase" what was left in the real track positions, if its less than 90 degrees away from the adjacent "real" track.

So what you do is get data "clobbered" together. the drive reads the new data, and the old data at the same time, causing errors.

If its fully mis-aligned, that means your new tracks are equidistant between the leading and trailing track records, so the head cannot "see" the adjacent recorded data. The floppy will write and read just fine. however, will not read in ANYTHING else unless the drive has the same alignment. (i have done this before. )

 

[techknight]

Also, as a side note, the stepper motors wear out with age as well, and cannot make uniform degree steps anymore. steps become "variable" and the alignment will wonder all over the place. keep this in mind as well. As any personal cases, i have NEVER seen that myself. but its certainly possible.

 

[waynestewart]

First thing I'd try is cleaning the drive head with either a head cleaner or a q-tip and isopropyl alcohol. That seems to solve the problem in 95% of the cases where the drive isn't gummed up with congealed grease

 

[Mk.558]

I will head on down soon to a computer place of some kind and see if they have floppy cleaner disks.

A floppy drive on a Compact Mac isn't allowed to fail, for any reason. Just like a differential in a RWD vehicle: it should never fail, for any reason, barring lack of lubrication upkeep or excessive power. Ever. I shouldn't even have to think about it. Okay if it's a limited slip diff and it gets noisy at 600k KM (about 400k miles) that's probably okay, but it should never catastrophically fail. (And the limited slip assembly should come out easily, and the rear cover should have both fill AND drain plugs -- none of this procedure where you suck it out of the fill plug with a vaccum pump (I once spent 45 minutes getting maybe half of it out on a late mode Explorer))

 

[Mk.558]

Mis-Alignment for sure.

Something tells me you are capable of doing this? If that's so I have two FDDs that could use it.

I just ran a cleaner disk that I got off Amazon through it, and it's still the same as before.

 

[techknight]

I could if i absolutely HAD to. but i usually dont, as its very tedious. hehe.

Remember the old sony mavica floppy cameras? ive dropped a few in my time and they almost ALWAYS knock the disk alignment off. had to fix em. and i wished not to after the job was done. lol.