OSI Challenger II

From: Bill Sudbrink <wh.sudbrink_at_verizon.net>
Date: Tue Feb 22 21:55:02 2005

> I'm looking through said machine while I'm in temporary
> custodianship of it and there's a couple of oddities. The
> Challenger itself (the one in the Big Blue Case from about
> 1980) has a 500-series 8 position backplane

My March 1979 price list shows the 580 as the 8 slot backplane.

> and features a '502' CPU board with 6502 chip, 8K RAM and
> a '540' monochrome video board with keyboard connector and
> a lot of kludges that are miraculously still wired in place.

Very common for OSI machines.

> Also on the backplane is what looks like a prototyping board but
> its moniker - 574 - doesn't appear in any official list of OSI
> boards I've found so far,

Price list shows the 495 as the proto-board.

> and there's a 4th board with '116RTC'
> written on it that contains a 6520, 2mhz xtal and much glue
> logic.....RTC to me is a realtime clock

Made by D&N Micro Products of Fort Wayne, Indiana.
>From their July 1, 1979 price sheet:

================================================================
NO. 116RTC

Crystal controlled Real-Time Clock. 12 or 24 hour format
Event timer - up to 99 Hrs., 99 Min., 99 Sec., 99/100 ths. Sec.

$139.00
================================================================

Ah! Just found the spec sheet for it... a bit too much to type
in right now... Basically, in addition to the above:

External run and stop inputs provided to time external events...
8 buffered outputs to drive relays, LEDs, etc...
8 bi-directional ports as well...

This board no longer appears on the Sept 1981 price sheet.

> so I'm puzzled as to why a 6502 based micro with seemingly 1 video
> out (plus an RF modulator dangling precariously from its handwired
> position) and 1 RS232 connection might need an RTC board.

The 540 might have X-10 on it as well.

> There are also many wires going all over the place that I need to trace as
> well as a load that don't go anywhere :) 'rah.
>
> Pix available if anyone wants them.

Love to see them!
Received on Tue Feb 22 2005 - 21:55:02 GMT