9 Dec
2010
9 Dec
'10
1:40 p.m.
Tony (and anyone else interested),
I am seriosuly wondering why I am the only person responding to this,
given that I've never seen a Lisa 'in the flesh' and have certainly never
been inside one. But I don't mind helping...
Here is the symptom on this Lisa 2/10 (or Mac XL as they are also called
sometimes).
It passes all tests until it gets to the I/O board test. It then fails with
an error 57 message (disk controller fault). Reading Lisa 2 documentation
It would be very useful to know if this is a floppy controller error or a
hard idsk cotnroller error.
Should a Lisa 2/10 be able to boot from the floppy drive if there's no
hard drive connected? If so, it would be worth trying to get that working
first.
suggests this is the Lisa Lite adaptor, but with a
Lisa 2/10 there is no
such thing. The floppy disk is connected straight to the I/O board. I am
not sure if the fault is on the I/O board itself, or somewhere on the Widget
hard drive controller? I've found the schematics, but no real "theory of
operation" docs for the widget drive itself.
The Lisa allows you to click on both the hard drive icon or the floppy drive
icon even after the error is posted. Neither work. The hard drive comes up
with an error 82 which means "Drive doesn't answer". I can't recall
right
OK, I assume the Widget is spinning, etc.
I will take a look at the schematics for the I/O board and the Widget. I
wonder if it's posssible to easily see if the machine is even trying to
access the drive.
now what the floppy error is, but it doesn't spin
up or eject, even with a
DD drive.
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.
I suspect the fault is on the I/O board itself as the floppy seems dead even
when the hard disk is disconnected. However, I'm not assuming anything.
I wonder if there's some common circuit (address decoder, buffers, I/O
chip) that's common to both disk controllers. I will have a look.
This may be just because the I/O has reported an
error, or it's
functionality may need the widget drive to be on-line.
Some other things...
1. With the widget and floppy drive unplugged, the same error occurs (but
this might be because they ARE unplugged). The error also occurs with
either one or the other plugged in
On the other hand it may mean the system is not looking for either of
them for some reason, and therefore doesn;t notice they are not connected.
2. When I switch on, the widget drive spins up, the drive light flashes and
I "think" I can hear the "clack" people write about when the brake is
released. It's quite noisy but I believe these drives are.
3. I've cleaned all the card edges.
4. I'm fairly sure I have the right ROMS. The machine reports H/E8. H is
correct for the Lisa 2/10. E8 (which refers to the floppy disk routine I
think) is not documented anywhere. 88 seems more common. It may be a later
revision.
5. The I/O board looks in good external shape with no evidence of corrosion
anywhere.
6. I've reseated all socketed ICs I could find, both on the I/O board and
the widget drive.
I have a scope, logic probe and multimeter. I also have the schematics. I
have a website where I can post pictures if needed for diagnostic purposes.
I have "some" skills at interpretation but I would still class myself as an
"advanced beginner" so any guidence as to where I might start is most
welcome.
A few very quick checks (I hope).
1) Check the power supplies at the floppy drive. Unlikely to be the
problem, but let's eliminate it.
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?
3) What abotu the Widget interface conenctoe? I will see what the signals
should be there...
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?
-tony