Are leaky caps a problem on external FDDs?

[Nicholassuperfrog]

I opened up my external 800k drive, hoping I could fix it and get it to work with my 512k. Removed the old grease, added new grease, and thought everything would be good - but it seems there’s an issue with it still.

The eject mechanism works fine now, but it doesn’t read disks (and honestly, I can’t remember if it ever did). 

It looks like the circuit board has some layer of.. something on it. It wasn’t too obvious at first, but I noticed that my Q-tips were turning a brown/yellow color when I did a little cleaning with some alcohol. 

Would this be a cause for a dead Mac screen? I think I get error code F0040 or something like that 

 

[tanaquil]

Error code ending in 40 might be a bad/unrecognized disk error (hence related to the drive) - can you copy down the exact error? Some other F errors have to do with bad RAM, etc, but those usually end in smaller numbers.

Are you able to start the 512K with a known good disk in a working internal drive? Does the same disk then fail in the external drive? Good to eliminate other possible causes of failure before you try to isolate what's not working on the external drive.

Note that an unmodified 512K can only read 400K disks even in an 800K external drive. If your 512K has a model number ending in E rather than W, it should be able to read 800K disks as well as 400K.

There is no way to visually distinguish between 400K and 800K floppies, since they both have the single hole; you just have to inspect the capacity in a drive/computer that can read them.

I don't know about circuit board repair for floppy drives, maybe someone else here will know. Another problem that can occur is that if the drive head was bumped or stretched too much during cleaning, it can knock the head out of alignment, which is pretty much an unfixable problem AFAIK. (To avoid this, don't raise the black plastic piece too high when messing with the drive.)

Yet another problem that can occur is something wrong with the stepper motor - again, I don't know if this can be fixed by a hobbyist. But other causes, like disk incompatibility, should be ruled out first.

 

[Dog Cow]

Would this be a cause for a dead Mac screen? I think I get error code F0040 or something like that 

You're probably seeing 0F0064 which means there was trouble with the startup disk. One cause is trying to use a 800K double-sided startup disk in a single-sided drive. 

Note that an unmodified 512K can only read 400K disks even in an 800K external drive. 

That's not true. A Mac 512K can boot from a 800K drive. Read this article on Using an External 800K Disk Drive with Mac 512K

 

[Skate323k137]

The "layer" on the PCB you are worried about is almost certainly flux and nothing to worry about. My SE/30 had a ton of residual flux on it when I recapped it. Nothing to really be concerned with though you can clean it up with alcohol and q-tips as you found, but I wouldn't bother. 

Stating the obvious, did you run a cleaner disk through it?

 

[Nicholassuperfrog]

Error code ending in 40 might be a bad/unrecognized disk error (hence related to the drive) - can you copy down the exact error? Some other F errors have to do with bad RAM, etc, but those usually end in smaller numbers.

Are you able to start the 512K with a known good disk in a working internal drive? Does the same disk then fail in the external drive? Good to eliminate other possible causes of failure before you try to isolate what's not working on the external drive.

Note that an unmodified 512K can only read 400K disks even in an 800K external drive. If your 512K has a model number ending in E rather than W, it should be able to read 800K disks as well as 400K.

There is no way to visually distinguish between 400K and 800K floppies, since they both have the single hole; you just have to inspect the capacity in a drive/computer that can read them.

I don't know about circuit board repair for floppy drives, maybe someone else here will know. Another problem that can occur is that if the drive head was bumped or stretched too much during cleaning, it can knock the head out of alignment, which is pretty much an unfixable problem AFAIK. (To avoid this, don't raise the black plastic piece too high when messing with the drive.)

Yet another problem that can occur is something wrong with the stepper motor - again, I don't know if this can be fixed by a hobbyist. But other causes, like disk incompatibility, should be ruled out first.

Thanks for all that! I’ll copy down the exact error when I get home. The mac’s Internal drive is seized up (I’d like to fix that as well, but figured I should do a practice run on this external drive first). But I have indeed booted it up successfully with a MacPaint/System disk in a different external drive (Mirror Magnum 800). 

 

[Nicholassuperfrog]

The "layer" on the PCB you are worried about is almost certainly flux and nothing to worry about. My SE/30 had a ton of residual flux on it when I recapped it. Nothing to really be concerned with though you can clean it up with alcohol and q-tips as you found, but I wouldn't bother. 

Stating the obvious, did you run a cleaner disk through it?

Thanks. I’ve heard about flux but I guess I wasn’t sure what it looked like. I haven’t run a cleaner disk through it (any brands you’d recommend?)

I did try to clean the heads with a q-tip and 91% alcohol - hope I didn’t damage them in the process..

 

[tanaquil]

I haven’t run a cleaner disk through it (any brands you’d recommend?)

I have used this one. There are half a dozen other brands on Amazon that probably all work the same way.

Basically the stuff is just alcohol, I think, but it has the advantage of avoiding direct contact with an object that could damage the heads.

 

[Dog Cow]

 But I have indeed booted it up successfully with a MacPaint/System disk in a different external drive (Mirror Magnum 800). 

You need to see if you can initialize a disk in the 800K drive that's giving you trouble. If after cleaning the heads, as you say you've done, the drive cannot initialize and read a disk that it formats, then you know there is some deeper problem than a dirty drive.