Re: Extended 80 column card issue

[dempson@actrix.gen.nz (David Empson)]

Jeff Shanholtz <jeffsubs@shanholtz.com> wrote:

> On May 23, 3:02 am, Linards Ticmanis <ticma...@gmx.de> wrote:
> > And what about the build-in self test (hold CloseApple during power up),
> > does that pass?
> >
> > Then there is that "Call-A.P.P.L.E. test disk" that when booted on a //e
> > should give you an option to test aux memory. You can try that. The ROM
> > test on that disk is expected to fail on an enhanced //e by the way,
> > since the disk came out before the enhanced ROMs and doesn't know about
> > them. And DON'T use the drive alignment test on that disk to actually
> > modify drive alignment, it does a lot more harm than good.
> 
> Now we're talking! I didn't know about the closed apple self test. I
> don't even think I knew about that as a kid!
> 
> It reports: "*RAM ZP 1 0 0 0 0 0 0 0". Anyone know what specifically
> that means or where I can look that up? A google search on "apple ii"
> "ram zp" didn't turn up anything.

The "*RAM" means it is complaining about auxiliary memory.

ZP means it is testing the zero page area of auxiliary memory (locations
$0000 to $00FF) and found an error. It might actually be using "ZP" as
an abbreviation for "Zero Page and Stack", as they are accessed via the
same soft switch, in which case the error could also be in the $0100 to
$01FF area. (In theory it could also extend to the language card area in
$D000-$FFFF, which is also on the same soft switch, but I'd expect the
self test to display an error differently for that area, especially as
there are multiple banks that would need to be described.)

The 1 in the first position means that bit 7 (I think) of memory in the
zero page area of auxiliary memory. If it is always reporting the same
error, it sounds like you have a single faulty RAM chip.

The 80-column text screen uses $0400-$07FF in auxiliary memory, and as
that seems to be OK, it sounds like you have a RAM fault localised
within a specific range of addresses.

-- 
David Empson
dempson@actrix.gen.nz