-----Original Message-----
From: Allison J Parent <allisonp_at_world.std.com>
To: Discussion re-collecting of classic computers
<classiccmp_at_u.washington.edu>
Date: Sunday, March 21, 1999 9:39 AM
Subject: Re: SWTPc 6800, common format (sharable?) repair journal?
><and transister( 18n9 ) from rectifier bridge. The soldering job on MP-A2
><has alot of resin around connnections that I'm already pretty leary of.
Il
><start off by digging for all the hardware documentationI can find...
The documentation is great. Including just the spine of the yellow SWTCP
binder for the docset. The Computer System Addendum listed everything I
should find but it gets pretty unorganized at section 3. Out of Section
1(hardware) I'm missing a page, PIA-9 & PIA-10. I'd ask for a copy now but
I think I may have a few more to add
>Wash with alcohol, then put in dish washer to clean up the boards.
Really? It seems like microscopic moleculer soap minutia or the drying
cycle heat would try and hurt some of the ic's.
>The bulk of the SWTP hardware was hand assembled so removing the resion was
>often not done.
>
><First question: The baud lines on both busses (110,150,300,600,1200) caug
><my eye and that ad above states: "Crystal controlled oscillator( 1,7971 )
><provides the clock signal for the processor (before?) and is divided down
b
><the MC14411 (both on MP-A2 GK) to provide the various baud rate outputs
fo
><the interface circuts. Full buffering on all data and address busses..."
><Does that mean that all these cards are serial?
>
>No! They had a common baud rate generation to avoid repeating a circut
that
>generally appears on every serial card. It was one way to reduce the cost
Architected to accomodate many (just?) serial cards?
>by elimintaing redundant circutry. the transfers were via 8bit dat and
>16bit address plus a hand ful of control lines. It was compact hence the
>name SS50 for the bus.
What does the full buffering on all data and address busses mean?
I think the TOP of MP-B is the most artistic layouts I've seen
>Allison
>
>
>
- Mike: dogas_at_leading.net
Received on Sun Mar 21 1999 - 09:13:08 GMT