68k FLoppy issues. Can't read disks, for some reason.

[johnsonfromwisconsin]

I'm having a bit of an issue going through the vast array of machines and floppy disk's I've "conquered" lately.

My Quadra 650, Mac IICi, and SE FDHD all runing some form of System 7 read virtually every disk unreadible...

Ah well, so they lost their data. Floppy disks aren't stone tablets, afterall...

Well, I tried to format a few of the unmarked floppies that couldn't be read and they all fail to initialize for reasons that disk is damages, or something.

Okay, well, floppies do get damaged and die, I imagine.

My Windows XP Box can format them no problem, as can my 7300/180. I try a few more which are unreadible on the 68k Macs, but the Powermac running 8.1 can read them no problem, including my system 6.0.8 disks on 800k disks.

Why are the 68k Macs having trouble reading everything?

 

[Mike Richardson]

Try blowing some compressed air in the floppy drives. That fixes it for me most of the time. You may also need to run a cleaning diskette. If those don't work, then the drives are probably defective.

 

[tomlee59]

Floppy drives can suffer from numerous ailments -- dirty/misaligned heads and balky mechanicals are the common ones. As Mike said, a good clean will often do wonders. Here are some troubleshooting tips:

1) If a drive can successfully read a disk that the same drive also formatted, but it cannot read disks formatted by a different Mac, then the problem is likely a misaligned head.

2) If a drive cannot read a disk formatted by any Mac, but that disk is known to be readable by other Macs, then dirty heads or some mechanical problem is likely the reason. Clean the heads first. If that doesn't solve the problem, you'll have to get at the drive and disassemble it. You'll likely find that the chassis lubricant has morphed into a glue-like substance. Carefully and thoroughly remove it (WD-40 on a cotton swab works well), then re-lube (don't overdo it).

A thorough head and chassis clean will fix most of the common floppy drive problems.

 

[johnsonfromwisconsin]

Okay,

I have one spare auto-inject drive in the pile of disks that came in all that crap I got. I installed it into the IIci and it seemed to work, for a while. Now it sporatically works.

Same for the IIsi machine. the SE doesn't work at all. I've cleaned them out with air and have cleaned the heads. I guess I'll be looking for replacements....

 

[johnsonfromwisconsin]

You know,

the more research I do, the more I find that 90% of problems with floppy drives are mechanical in nature (IE cleaning and lubing). I am going to tear into these things and clean them thoroughly, including using more than just air on the heads. It's possible that a thin layer of oxidation is what's causing the inconsistency in head reading. I plan on using alchohol.

Anyone have a good guide for doing this properly?

 

[porter]

I plan on using alchohol.
Anyone have a good guide for doing this properly?

Pint glasses, an easy chair, good company, pleasant music.

 

[tomlee59]

You know,
the more research I do, the more I find that 90% of problems with floppy drives are mechanical in nature (IE cleaning and lubing). I am going to tear into these things and clean them thoroughly, including using more than just air on the heads. It's possible that a thin layer of oxidation is what's causing the inconsistency in head reading. I plan on using alchohol.

Anyone have a good guide for doing this properly?

Oxidation of the heads is rarely a problem (the heads are made out of pretty stable materials that do not oxidize), but a buildup of oxide grime from floppy media is pretty common, along with dust bunnies and such. It's pretty much the same degradation mechanism that causes video and audio tape heads to gum up with use, and so the solutions are the same: A gentle clean.

In the case of the floppy drive, as mentioned previously, the chassis lube can turn gummy, and prevent proper operation. One of the failure modes is that the heads are thwarted from loading fully onto the media. Once you remove the drive, you'll be able to see very quickly whether this is the problem.

And yes, most of the problems are mechanical in nature, and are simply fixed. As long as no one violently yanked out a stuck floppy (an act that can rip the heads clear out), most drives are readily fixed.

 

[Scott Baret]

There used to be drive cleaning cartridges that looked like floppy disks (and went in the drives like floppies). This was similar to the VHS head cleaner that used to be sold.

There used to also be disks that were advertised as self-cleansing. I think Sony made them and I think 3M did too (they made Scotch VHS tapes that were supposed to help clean your heads as well). While I was skeptical about these disks at first I have been using the newer 3M disks in a Classic and have found the gumminess of the floppy drive is far less than when I got it–I don't even have to push the disks in as hard as I used to! Perhaps 3M disks do clean drives?

Look for a Read-Write cleaning disk. Your next best bet is the 3M disks that clean heads. I haven't used the Sony disks in a gummy drive.

You can also use compressed air, but be careful with it. The bottle can get COLD, so don't spray for extended periods of time. You also don't want to breathe it; I wear a surgeon's mask when I spray compressed air.

 

[MrMacPlus]

If the dust isn't caked on the drive you could use a vaccum..

 

[johnsonfromwisconsin]

None of the drives are that dirty, and they seem to operate just fine mechanically. I'm kinda scratching my head right now...

 

[johnsonfromwisconsin]

I cleaned the rails thoroughly and lubricated lightly of one subjet. Observing the drive with shield off, the heads move, seem to be making contact with the disk (confirmed good disk) and still gets bad disk error when initializing.

Also, this happened to a second. I think there's a reason I got all these macs so cheap



How much do auto 1.44 drives go for anyway?

 

[tomlee59]

If the drives won't read disks that they themselves formatted, then that's a sad day. Just for yuks, though, have you tried doing this on a given disk more than once? If the heads are badly misaligned, I find that more than one pass is sometimes required, if the floppy disk has previously had data written to it -- the erase operation apparently doesn't quite succeed in wiping out bits that were written strongly some distance away.

 

[johnsonfromwisconsin]

If the drives won't read disks that they themselves formatted, then that's a sad day. Just for yuks, though, have you tried doing this on a given disk more than once? If the heads are badly misaligned, I find that more than one pass is sometimes required, if the floppy disk has previously had data written to it -- the erase operation apparently doesn't quite succeed in wiping out bits that were written strongly some distance away.

Actually, they won't even complete a format no matter what I do, even after several attempts.....

 

[wally]

My two cents worth: You can test to see that the heads make sufficient mechanical contact for reliable operations (I'm assuming you have already successfully tried a known good floppy drive in each of your machines to eliminate bad floppy controllers, cables, power supplies, and possibly abusive connections to the external floppy connector by previous users).

There is a two stage trigger mechanism that you can manually operate to close the mechanism without a floppy: viewed from the front, one pin needs to be pushed to the right side, then the rear pin needs to be pushed backwards (both of these pins are connected by one top mounted spring on the right top side). With the loading platform now closed, you should look to see that the two heads actually touch, with no light showing between them at all. The space between the plastic tab that lifts the upper head, and the plastic track below, should be at least 1 mm, more than the thickness of the tab. The platform should be in the fully dropped position which means the four bearing rings should be bottomed out in direct contact with the eject slide in the fully forwards position (you can wiggle this to identify the slide, it is integrally connected to the manual eject tab in front).

If you take a new US $1 bill and place it between the two heads and hang it vertically, the weight of a single penny taped to the bill should be supported, but two pennies taped to the bill should extract the bill. On my SE/30 floppy there is a small semi-hidden coiled spring pulling down against the force of the upper leaf spring that supplies this tension.

I have seen only one case of "spread head" on a liberated machine and do not know if it resulted from someone over-separating the heads in attempted preventative maintenance or forcible extraction of a stuck floppy.

 

[wally]

[8)] ]'> I just noticed that the low level signals to and from the heads are carried by flex PC conductors terminating in tin plated connections (at least on my current SE/30 reference unit). Over time, this is known to be NOT GOOD, leading to intermittent and/or poor connections. To test, simply unplug and re-insert both head connections and retest. Probably not a bad idea to reseat all of the other connector pairs also. Low voltage/low current tin to tin connections are vulnerable even in clean lab conditions, and especially so if the machines are stored in uncontrolled climate extremes (any of these where you live?).

 

[tomlee59]

Wally brings up a good point, as always. If you feel so inclined, you can check the low-level head connections with an ohmmeter, after performing the obligatory visual inspection of the area in question. Instructions are toward the end of the doc at http://68kmla.org/files/classicmac2.pdf