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Bother with recapping floppy drives?

Posted by: olePigeon on 2023-03-28 10:43:48

I had a marathon clean / lubrication with some troublesome floppy drives I have. Ran into a few inconsistent issues that (sometimes) swapping parts around fixed, such as swapping heads around from different mechanisms. Some heads work better than others, even though they've all been thoroughly cleaned.

I was wondering about the caps, though. There're six capacitors on the Sony HD drives. One of my drives is a first revision -01G drive, which means it shipped back when the SE and II were getting FDHD upgrades. The others are all later revision -21G. So those caps are old. They're not surface mount, though, like the LC and IIci, so I doubt they've leaked any significant amount. And floppy drives aren't high power devices, either. Well, there are a couple 50v rated caps in there.

Do you guys think we should bother with recapping floppy drives? Or just leave them? A few of my floppy drives are just intermittent with their issues, and no swapping of parts or half-assed calibration will get them to work reliably. So I do wonder if caps could be an issue.

I know a lot of people hate the shotgun approach to repairs, but caps are relatively cheap and easy to replace. I also don't have an oscilloscope (or even know how to use one if I did) to be able to properly diagnose and calibrate a floppy drive.

Posted by: olePigeon on 2023-03-28 16:32:45

Well, I guess I'll order a few and see if it makes any difference on a some of my troublesome drives. I'll try to remember to report back.

Posted by: Skate323k137 on 2023-03-28 17:03:59

I don't know much about calibrating newer drives. In the absence of an oscilloscope, ye Olde 5.25 drives could sometimes be calibrated with a strobe, kind of like how a vinyl turntable strobe shows a steady pattern on the dots of a spinning platter at proper speed.

I got an oscilloscope recently, at least in the grand scheme of things compared with other equipment I use. I am usually a RTFM / written learner but I found YouTube to be indispensable. It took me less than an hour to check the calibration of the probes and learn to check a clock frequency, finding a crystal oscillator running at 1/3 of its marked rating. One of those things I haven't used much but when I have needed it, it's been amazing.

Posted by: dochilli on 2023-03-28 23:01:56

Here someone described a zero track alignment procedure that worked for him.

SuperDrive (floppy) maintenance

Hi Guys, On the infamous “zero track alignment” issue with the floppy drives… I fixed many drives in the past with the most usual “trial and error”, luck-driven and unnerving approach. This time I opted for something more structured, which has proven to be rather successful (read: not much...

tinkerdifferent.com

I have the same problems with some drives. So I am interested if you have a solution for your problem.

Posted by: volvo242gt on 2023-03-29 01:31:42

^I've used the same procedure to resurrect a few of the drives around here.

Posted by: LaPorta on 2023-03-29 02:32:28

I've wondered this a few times. I have never recapped them, but I always wonder if the day is coming. Then again, might they be akin to the caps on an SE logic board that so far are "bulletproof"?

Posted by: CC_333 on 2023-04-02 00:07:04

It seems like, at least for relatively low power, low heat situations, there was a sort of "golden age" of capacitors where certain through-hole parts (such as those apparently used on many, if not most 128k/512k, Plus and SE logic boards) seem almost immune to leaking. Kind of like those old soldered Varta PRAM batteries that won't die.

Why is this, I wonder? And are the capacitors on these floppy drives going to be so lucky?

Perhaps Apple used higher quality parts for some reason?

c

Posted by: s_pupp on 2023-04-02 07:09:11

I recap floppies. I figure that, since longevity is the goal, it’s better to be safe than sorry.

Posted by: desertrout on 2023-04-02 08:04:14

I've recapped a couple 1.44 drives in a shotgun attempt to solve issues (which it didn't), but it did seem like the caps needed to be replaced - a bit of leakage, especially the two by the motor. Considering though these caps are so inexpensive and easy to replace, why not do it?

Posted by: olePigeon on 2023-04-02 19:41:20

So, good news and bad news. Bad news is, recapping did nothing to fix my problematic drives. Good news is that I discovered that these tiny caps leak pretty bad for their size, especially the two near the rear. Even with my fume extractor on, it stunk up my room as I removed the old caps.

So I think it's not a bad idea to recap even if it doesn't really affect the performance ... yet.