apple Lisa2. One working!! - one to go?

[terry stewart]

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