Today I decided to look at the external floppy drive that I got from a bundle of so called working retro stuff.
The floppy had this problem, it would just keep spinning whenever I put a floppy disk inside it. So I decided to have a go at it, so I opened it up, gave it a full cleanup and decided to just change the capacitors on it, since this is usually the fix on retro floppy drives like these. It turned out that this drive did not have any SMD electrolytics. Instead it had 3pcs 22uF @ 16v, and 1pcs 1uF @ 50v shown below
I decided to pop them out, Insert new ones, and presto! The disk drive worked again. I made sure to clean the stepper motor mechanism while in there and added a small amount of oil on all moving parts.
Usually these kind of caps dont need to be changed, but in this case one of them did. Because I often repair old stuff, I decided to buy a quality instrument to diagnose caps. My choice was the PEAK atlas ESR+ model ESR70 and it is just a dream to work with, but its kinda expensive for the hobbyist like me. But the Atlas did its job and found the culprit. Since one of the caps had way too high ESR, I figured I found the one causing problems.
Of course, when you buy used stuff that dont work, it has often previously been opened by someone. This was also true when it comes to this device. It was aparent by the 3 lacking screws in the bottom, but fortunately, I have a nice stock of replacement screws, so now it is both clean inside and out, and it has all the screws again. …and new caps. I tried it on my Atari 520 ST. It works great, and is also surprisingly quiet. Now to play some Atari games!