Apple 20SC SCSI HDD - Recap? Oil instructions?

[ClassicMacintosh]

Thorough search for attempt to revive - seems like it's a good idea to oil the motor?

Can lithium grease be used? Or should it be a machine oil?
Exactly where should it be put and what needs to be rotated?



Does the drive need recapping? Have circled the obvious ones with excellent mspaint - they look dry.
Thanks

 

[robin-fo]

Is this a Miniscribe? Oil is probably needed, but the capacitors should be fine. I‘d use sewing machine oil. Don‘t rotate that part if you don‘t have to. Let the drive spin up a few times and it should be fine.

 

[Franklinstein]

Looks like our old friend the Miniscribe 8425S.
Assuming the disk drive functions, first I'd consider getting a dump of the PROM.
The caps appear to be solid, so they should be fine.
Don't rotate the interrupter unless, when the drive spins up, the interrupter doesn't move at all. If it doesn't move, wait until it starts making sounds like it's trying to move (usually a horrible groaning noise) and then give it a gentle nudge. You can really only oil the front bearing since the rear is obscured and there's no way to get the motor off without potentially screwing up head alignment and rendering your data unreadable. If you want to oil it, light machine oil (or possibly synthetic 5W30 engine oil) should be fine.

 

[ClassicMacintosh]

Thanks I'll give it some sewing machine oil and report back - have got synthetic 5W30 but it feels a bit wrong!

@Franklinstein that's exactly what it is! Heaving and groaning something awful, it is. How would one consider dumping the PROM?

 

[Franklinstein]

ROM dumping is easy if you have a chip programmer (such as the XGECU TL866). You just pull the chip, drop it into the programmer, read it, and put it back in the drive.
If you don't have a programmer, don't worry about it. It's mostly an optional tech archeology sort of thing. If your drive works otherwise it's not necessary.

You can try getting a hair dryer and heating up the stepper motor a bit (if you have an IR thermometer I wouldn't heat the motor over 100F/40C but if not using a hairdryer vs. heat gun will help keep it from getting too hot) before trying to turn it on. Tip the drive on its side and put a little oil on the motor shaft and the heat should help it work its way in.

 

[ClassicMacintosh]

No programmer unfortunately, so will continue to attempt the revive.

Followed all of the above - drive is on side, oil in motor, heated gently. After an hour or so, booted with drive on side. The motor turns just fine it seems, but now it starts with a solid orange light and one-two clicks, maybe 100 of them (clik-clik, clik-clik). After this, the motor moves again, then and it goes to flashing orange (one sec on, one off), with what sounds like single clicks (click-click-click-click) every ~2 seconds.

 

[Franklinstein]

Sounds like it may have lost its alignment or possibly track 0. Does it have important data on it? If not, if it shows up in Disk Utility (assuming you're booted from a floppy or something) you can try a low-level format.