31 Dec
2012
31 Dec
'12
11:05 p.m.
Hi Win,
Yes, bad RAM could definitely cause that. The board you have was
manufactured by ON THREE, which got its start as an Apple III users
group. Once Apple turned its back on the III, ON THREE stepped up and
began producing its own hardware and software for the computer. Apple
had advertised the III as being expandable up to 512K, but never
released a board larger than 256K. As the ON THREE engineers
discovered, it required some new ROMs and additional addressing lines,
but they got it working. That 512K board is fairly rare and sought
after by III collectors, as SOS and big programs like Pascal can
really benefit from the extra room.
I'm not sure how easy it is to locate replacement chips for that board
these days. Last time I checked (a few years ago), they were still
available if you knew where to look. I have a few extra RAM boards
for the III (256K and 128K, though - not 512K). I could loan you one
for troubleshooting purposes, if you're interested.
I wrote a quick blog entry a while back about ON THREE's card:
http://www.6502lane.net/2011/01/17/a-look-at-on-threes-512k-memory-board-fo…
Also, I have a PDF version of the user manual that came with it. The
links in that blog entry are dead, but I can upload it, if you want.
- Mike
On Mon, Dec 31, 2012 at 1:07 PM, Win Heagy <wheagy at gmail.com> wrote:
Mike,
Another follow up that probably sheds a bit more light on my Apple III
issue. I tried copying some additional disk images today. I tried the
CFFA SOS image, but it exhibited the same behavior as the other SOS
image...the floppy drive spins for about 3 sec and then nothing. On a
whim, I tried the RAM test image. It worked and brought up the RAM test
screen and began the test. It stops and indicates bad RAM where shown in
the pic in the imgur link below. There appears to be third party RAM in
this III. Is that common? Is there a way to test without that RAM that
would be recommended? I did reset all of the RAM chips on the board, but
it still fails at the same location.
http://imgur.com/a/c40m0
On the bright side, I'm thinking this is a good sign for the floppy
drive...the down side is obviously RAM issues.
Thanks,
Win