11 Dec
2010
11 Dec
'10
11:31 a.m.
Hi Ray,
Thanks for commenting,
But if you had a working IIGS would you sacrifice its
IWM? :-)
Of course you wouldn't (-: Luckily places like arcadecomponents.com do have
such things for sale. Unfortunately they don't have Lisa ROMS
I know you've said you're sure the I/O ROM
says E8, does the sticker on
the I/O board confirm this? It's very suspect to me.
No I corrected myself in a later post. It's actually H/EA which is maybe
even wierder! Consider I'm in New Zealand though, and I've noticed
sometimes our components can be slightly different (maybe due to 240v?).
Also can you confirm that the floppy drive in that
Lisa is a standard
sony 400K one? If you take it apart, do you see only one head, and the
top part of the clamp has a bit of foam?
Yes, it's definitely 400k.
If that ROM is ok, it might well be the 800K ROM from
SunRem. I'm
guessing that it's either that, or it's corrupt.
Well, it could be either of those I guess, but it definitely is an Apple
ROM. I've searched hard but haven't found what version the 800k ROM uses.
Did Apple themselves ever bring a 800k one out?
If either of those
cases is wrong, well, you might have a new ROM that wasn't unreleased.
Again, you're getting error 57, which is a timeout of the controller's
self test, or a bus error during an attempt to access the controller.
This has nothing to do with access to the floppy drive, but everything
to do with the power on self test that 68000 does to check the 6504 is
working.
Yes, that's what I suspected.
Unless the IWM caused the 6504 to crash, it shouldn't cause a bus error
or timeout when the 68000 tries to get status from the 6504. If on
poweron the 6504 is fully functional, it does a self test also. Then,
it writes the results into the shared floppy RAM, and the 68000 reads
this status. Unfortunately, in all cases, you get the same error 57.
It might be a timeout, bus error, or an internal 6504 failure, or a RAM
failure.
The only clue we have is the oddball I/O ROM version. Please, check the
sticker on the I/O ROM. If it says 88 on the label, either the EPROM
went bad, or the I/O RAM is bad, or something went wrong that prevented
the 6504 from reporting its version to the 68000. Does the sticker say
E8 on it? Is there an Apple symbol on the sticker?
I'm sure it's a genuine Apple ROM. It has the same type of sticker than the
ROMS in the other machines (layout and font) and it's got a part number
341-0281-D plus a genuine Apple 84 trademark notice. I believe the usual
ROM is 314-0241-D. The H/EA is reported on the screen during the
self-tests. It's not on the sticker.
Here's what the code looks like, all roads lead to
57 (EDISK)
unfortunately, so we can't pinpoint exactly what went wrong. If you
have a logic analyzer with the ability to analyze running 68000 code,
and can catch the POST ROM going through this code, you might be able to
see where it dies.
No I don't have one of those or indeed the knowledge to drive it.
Perhaps if you can enter Service Mode, you could look
at 02AE which is a
copy of the result of the 6504's self test. If this is non-zero, it's
what reported the error. 02A1 is a copy of the ROM version, which
should contain E8.
No I can't enter the service mode. My keyboard (actually all three
keyboards) seem non-responsive in this respect.
From what you've written Ray, I'm starting to
think this repair might be a
bridge too far for me. I might have gone as far as I
can. The options
might be to shelve it and wait until I can either source an IWM, a
replacement ROM, (or even a new board) from somewhere else. Not that they
come up that often (-: At least I have a Lisa 2 that at least tries to
access a disk so there is hope I can get one of these units fully working.
It would have been nice to have the one with the widget on-line though.
Anyway, the feedback is appreciated.
Terry