Re: Apple /// resources?

[spec@vax2.concordia.ca (Mitchell Spector)]

In article travis@cluracan.remove-this-part.org (Ward C. Travis) writes...

>- First Question
>
>I have two Apple ///s. One seems to work fine, the other always hangs
>during a disk boot from the same disks that the other /// 'likes'. I've
>run the 'F6E6G' diagnostic

    Ah, so that is how you activate the built-in memory diagnostic. :)
You get into the (what appears to be) III Monitor and type "F6E6G"?

>on both and it goes on forever, never showing me any inverse one digits.
>So I presume the memory on both of them is fully operational.

    It will loop continuously if the keyboard lamp is burned out,
but I doubt that is an issue with you as that will also cause the
testing to occur immediately once you cold-boot the machine (Hmm,
then again, the looping may be normal since I was never able to
figure out how to invoke the self-test. I just know what happens
if the keyboard lamp goes dead).

>It 'sounds' like the one having troubles does some disk
>seeks, just the same series of sounds as the working one does, then
>there's a pause. It's like the system jumps out of the boot ROM into the
>loaded system and .. locks. I swapped in a working Disk /// on the dead
>system to be sure that the analog card wasn't trashing the data it was
>reading and got the same results.
>
>Anybody seen this? Is it something repairable, or a user error (mine)?

    Sounds like some bit of logic on the motherboard has failed, like
maybe one of the socketed TLL chips or a custom chip. I'm not really
that familiar with the III's motherboard so I can't really help there.

>Opening the cases, I find that both of the systems lack a chip in the
>socket at B-3. The /// FAQ says that this is the real time clock. I did
>notice that after setting the time on the working ///, the time never
>changed. Both systems also have a mount on the PCB, or well really a place
>for a mount on the PCB that should accept a coin-style battery. Are the
>systems missing the chip, the battery, or both?

    There is no clock in the Apple III, just an option to add one
(both a clock chip and I assume a battery of sorts with it). Sun
Remarketing has a few hundred in stock, or did a few years back.
The Apple III Plus added a clock chip and had a place to insert
batteries (they could be changed without opening the case).

>- Information for those with an interest
>
>The systems are both 5v systems, serial numbers in the 106000 range, and
>if I understand, this means they both have 256k (two full rows of 416's on
>the card).

    Actually they didn't start shipping with 256K as standard until
the Apple III Plus was introduced, although it was fairly common to
find III's that had been upgraded (or even purchased with) all its
memory sockets filled. The Apple daughterboard held 256K maximum, 
though you could replace it with a (rare) 512K board.

>Also, the two systems appear
>to have different revisions on the motherboard (different wire fixes -
>ECOs or FCOs - diffferent wire-wrap fixes). I'll post the ROM part codes
>if you'll tell me which ones are of interest (C-3? etc.).

    To my knowledge, there were only three major revisions done.
The first was the original Apple III, which was heavily populated
with chips and had memory inserted directly on the main board. The
next was the free board swap that replaced it, reducing the chip
count and moving the memory onto a raised daughterboard. The final
was the III Plus, which came in a slightly different case.

    There probably were minor in between releases, though with no
significiant changes (rather like all the revisions of II/II Plus
motherboard). I don't know if there were different ROM revisions,
in fact the III had very little ROM code in the first place--just
code to boot the 5.25 drive, a mini III system Monitor of sorts 
and a memory diagnostic mostly. Things like even the font used by 
the character generator had to be loaded in from disk.

Mitchell Spector
spec@vax2.concordia.ca