apple Lisa2. One working!! - one to go?
ard at p850ug1.demon.co.uk
Fri Dec 10 13:01:05 CST 2010
> > It would be very useful to know if this is a floppy controller error or a
> > hard idsk cotnroller error.
> Yes, I'd like to know that myself!
I'cve had a look at the I/O board schematics on thw web, the Widget
interface seems to be a parallel 8bit data bus + control lines, somewhat
akin to SASI/SCSI. It's implemented using a 6522 adn a little TTL.
The data lines are used for some other function (contrast control I
think), so if that works the 6522 is probably working. If there's a hard
disk problem it's in the Widget itself.
> > Right. This is a Sony 400K drive, as in the other Lisa, right? To
> > eliminate the silly faults, I would at least check the power at the drive
> > connector, and also see what the various signals are doing.
> Good idea.
>From the I.O board schematics, it appears the floppy controller and
interface is what I'd expect...
> > 2) Check the logic signals the floppy drive interface connector. Is there
> > any activity (changing signals) here? Anything chenge when you put a disk
> > in?
> Nope the drive is dead. And this time even with DD disks! Lights are on
> inside it though so it might be getting power. The drive's been
> cleaned/relubed and the platter turns. It would be worth me checking out
> the signals on the card edge though and comparing them to the working
That's what I meant. Do any of the signals on the interface conenctor
change when you put a DD disk in?
> > 4) The floppy coitnroller has its own 6504 microprocessor I believe. Can
> > you see activity (changing signals) on the address and data bus of this
> > processor?
> I swapped out with a known good one, and it didn't make any difference.
Err no. The point of checki nthe signals is not because I suspect the
6504 iteslf, but because I wanty to know if it's doing anything. A
microprocesosr cna appear 'dard' becuase it's not getting a clock signal,
or because it's being held in the reset state.
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