Commodore P-500

From: Larry Anderson & Diane Hare <>
Date: Tue Jun 24 00:53:54 1997

>From: steve <>
>Subject: Re: PET
> Hi you lot, glad the group is in a positive mood!!!
> Ok can you help ? a few months ago I found a Commodore P500 seriel NO. WG00837
Well if you collect Commodres, you are a very fortunate person!

> What the heck is it????
> Its made in W.Germany

> Any Idea??
> Steve

All I can do is give you the U.S. perspective on this machine, since I
haven't heard any stories on the European distribution of P-500s.

A few years back I picked up one (P-500) as well, with people telling me
it was a B-128, I didn't look at the back and was surely perplexed when
I needed to hook it to my 1702 and it came up in 40 column color when I
turned it on, so I did some research and asked around a few places (on
Q-Link, and a query to the Chicago B-128 users group). I received two
or three stories that were pretty much the same.

Back in 1982 Commodore re-vamped it's entire product line in order to
replace the aging PETs and to eventually phase out the then looking more
limited VIC-20. The line consisted of the Commodore 64 and Ulitmax, for
games/home/education use and the B-128 and P-500 for education/business
and as an upgrade option for people who purchased alot of PET (IEEE-488)

In its rush (given the home computer wars), Commodore sent a bunch of
demo units of the B-128 and P-500 to dealers (yeah, I know that sounds
strange, it was a different Commodore back then) these units were not to
be sold as they still needed to get their FCC certification (for low
radio interference). Well some of these dealers were offered quick cash
for the demo units (even though they had no manuals or anything) and of
course, they jumped at the chance. The FCC heard about these sales of
uncertified equipment and told Commodore to immediately cease any sales
of them and face stiff penalties. Commodore promptly recalled them (at
least the ones they could get). Well they finally certified the B-128
but I guess being that the Commodore 64 was so popular they abandoned
the P-500 entirely and it is said they destroyed all reamining P-500s.

At the time I talked to the CB128UG (1990?) they said I was the third
person in the world ever to report having one, and their estimation was
that there are ten in existence. (they would have known since they were
lent ALL documantation on the B-128 series from Commodore when they gave
up that B-series computers).

Ok the P-500 has a 6502 type processor (you know, like the 64) and 128k
of RAM, it has a SID sound chip (also on the 64 and B-128), a true
RS-232 port, cartridge port (I know of no carts avalable for the B
series) and IEEE-488 port. But unlike the B-128 it sports a 40 column
VIC-II chip, two joystick ports and ROM coding that supports the
datasette drive (the B-128 also has a connector but no programming to
use it). Both computers could accept an optional 8088 co-processor
board and make it capapble of running CP/M 86.

The RS-232 port has one pin designated (on both B-128 &P-500) for a
high-speed networking system that never went into development (but was
put in hardware, just in case) the guy from CB128UG was pretty impressed
with the stats on it which I forgot.

So to sum it up, the P-500 is essentially the Color PET or P-128 that
Commodore had talked about. Kinda a cross between the SuperPET/B-128
(128k, IEEE-488, true RS-232, Co-Processor), and a 64 (SID, VIC-II,
Joysticks, color).

Jim Butterfield made a memory map for the B-128 and has some programming
examples for the B-128 in Transactor issues which might get you some
information, but there are differences. My unit has a RAM problem and I
haven't been able to explore it too much, also the ROMs are pretty much
porototype and it runs like molassas, so I dunno how much good that
would do me when I eventually fix it...

If you do find out ANYTHING more (or even have a manual on it) I would
surely be interested in what you find out!

               Larry Anderson
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Received on Tue Jun 24 1997 - 00:53:54 BST

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