Hi Tony,
No, the widget is the hard drive in the Lisa 2/10. You are thinking of the
twiggy drives in the original Lisa 1.
Oh yes, of course. I've never actually seen a Lisa. let alone been
inside one -- and that is not likely to change.
I seem to remember that the Widget schematics are out there, if you need
them. I also seem to remember a few custom devices in that drive :-(.
I only had the "working" IWD chip in for a moment, just to see if the system
would pass it's internal checks hence prove mine was faulty. I didn't pay
too much attention to the widget error itself (error 75 from memory..which
means the machine thinks the system files are corrupt). Once I get my own
IWD I'll resume the diagnostic process.
It may be nothing more htan a corrupted disk, of course. Or it may be a
problem wit hthe drive.
Was the HDA a 'stadnard' one for the time? Surely Apple didn't make that
themselves. Was it, for example, the HDA from an ST412 or something.
The widget spins up and I can hear the "clunk" which releases the brake (a
good sign).
Does it try to move the heads? This drive probably uses a stepper motor
postioner, and often there's a metal 'flag' on the end of the motor
spindle outside the HDA which activates a slotted optoswitch for the
track 0 sensor. YOu can seee if this is moving when the machine accesses
the drive.
Yes, I think you are right. From my reading it seems
the IWD chip was used
in the early Macs and the Apple IIGS. The part shouldn't be that uncommon
then.
IWM = 'Integrated Woz Machibne', I believe. Does anybody know if there's
only one form of it, or several?
I was under the impression it was sort-of a single-chip version of the
logic on the Disk II controller board -- buty how close is it ot that
logic? Is it the same state machine, for example? COuld you make a
replacement using the know schematics and ROM dump from a Disk II?
-tony