5 Dec
2010
5 Dec
'10
10:26 a.m.
Hi Guys,
Anyone on the list have experience with the Apple Lisa? I'm having fun
ALas I don't ahve a Lisa (I can always dream...) But I may be able to
offer some advice.
Please be warned that last time I sent a message like this it caused yet
another almighty flamefest. Let's see if that happens again :-)
playing with three broken Lisa's (1 Lisa 2/10 and
2 Lisa 2s) I aquired about
a month ago. The aim is eventually to get the Lisa 2/10 and one Lisa 2 going
eventually.
The Lisa 2/10 comes up with a disk controller error during the I/O board
check. I don't have an I/O board I can swap out I've shelved that one until
I can get one of the other Lisa 2s going.
After a systematic check of what is and what is not faulty in the three
Lisas, I've now got one of the Lisa 2s to the point where it asks for a
disk. And here's the problem. I can't get any of my sony Lisa 400k 3.5
drives (all three of them) to show any sign of life? You can see the little
LEDs come on inside but nothing mechanical moves at all?
I have 2 LisaLite controller boards, but swapping these around makes no
difference.
I find it hard to believe that all three drives have exactly the same
problem or even that both LisaLite boards have the same fault (although it's
always possible I guess?). The only thing not swapped is the main cable
going from the backboard connector to the Lisa Light controller? However
the connecting ends look ok with no sign of missing or damaged pins?
\beign{rant}
There are some people I hope I never meet, beause if I do I will probably
do things that I come to regret (like when I'k in court for assault!).
The inventor of board swapping is one such.
\enf{rant}
This si a very clear example of why board-swapping on classic computes is
a very bad idea. Firstly, since you have no idea as to the health of any
of the parts, you can't deduce anything from the fact that swapping them
out makes no difference. Secondly, if there's somethign wrong that is
damaging parts (say 12V where it shouldn't be), you might well have just
ruined all the aprts you have. Oh well...
As I said, I know noting about the Lisa. But a Google search for 'lise
schematic' (no quotes) got me to a site with said scheamtics as the first
or second site listed. These schemeaitcs incldue the Lisalite board
(which I had never heard of) and the main Lisa boards, but alas not the
drives themselves.
If I am reading the schematics right, the Lisalite is an interface to
make a Sony 400K 3.5" drive -- presumably the same as the Apple Mac 400K
drive -- look something like the 'Twiggy' 5.25" drive. I don't think it
does a complete coversion -- like the PERQ (which I am muich more
familiar with), a number of the signals are software defined (they go to
I/O port chips), so obviously those could change in meaning. The Lisalite
board seems ot be really a PWM generatiro (using TTL chips that are easy
to understand) to handle the motor speed control.
As I said, there don't seem to be any schematics of the drive
available, and I've never worked on one (I have worked on the 80KK drive,
but that is quite different). However, IIRC one of the origianls volumes
of 'Inside Macintosh' has some information on the drive interface. Just
don't expect me to find it :-) I seem to rememebr that the control
protocol for thsie drive is a lot more complex than that for a normal
floppy drive, there aren't the expect signals on individual connector pins.
What I would do now -- actually waht I would have done first -- is grab
the Lisalite scheaatic and check the power lines are correct. Check that
there's 5V on the TTL chips, check that 5V and 12V are on the right pins
of the drive connector. Then find out (possibly from Inside Macintosh)
what is needed for the drive to spin. Presumably a PWM singal that's not
always 0, but is there a separate motor enable bit too? In any case, see
if the PWM scircuit is running, see if the machine is trying to talk to
the drive.
-tony