IBM PS/2 8530 720k floppy drive

[champagneandchips]

Two part question:

1. I am trying to revive a 720k floppy drive from a PS/2 model 30. The PCB on the underside of the drive had one of the surface mount capacitors fall off (C9, 22µF / 16V), so that's one obvious candidate to fix. However when I cleaned the area, it revealed that the pads were gone. I used the usual googling for this, but so far nothing showed up. Does anyone have a schematic I can use to see where to attach a replacement to, or knows how to fix that? By the looks of it, I'll have to take the whole thing out (is that safe to remove the rotating disk?) in order to find some of the relevant contacts.

Some of the identifiers on the board:

YG - 300E 94V - 0
6R020032. 01
Toshiba

2. Failing that, I have an adapter to put in a "regular" drive (not one with that custom edge connector that carries both data and power). Am I correct in assuming I need a proper 720k drive? I already tried it with a 1.44MB drive (which I know should work), but it doesn't seem to work (diagnostics complains about rotation speed being off, and trying to access any disk results in failure).

Thanks!

 

[Stinkerton18]

Judging from the photo, those two pads are already situated on two major buses. You should be able to scrape away some of the solder mask to use for the capacitor like so:

 

[Stinkerton18]

Oh and as for why you were getting speed errors, 720K disks are spin at a slower speed than 1.44MB disks, so yes the speed will be different and not match if you try to use a 1.44MB drive.

 

[champagneandchips]

Thank you. Upon closer inspection with a magnifying glass I was able to find the traces, and with a fibre glass pen scratched the solder mask away and soldered on a replacement. Not pretty but does the job.

Re the drive - it was the adapter that's bad, apparently. Swapped it out for the Texelec one and the same drive worked just fine (a 1.44MB drive, only recognised as a 720KB one, no speed or any other errors).

 

[Stinkerton18]

Ahh that's good then. Some older controllers really didn't like 1.44Mb drives and would result in data loss/corruption. Re: the solder job, it may not be pretty but if it works, it works. That's what counts in the end.