SWTPC 6800

Brad H vintagecomputer at bettercomputing.net
Thu Aug 4 09:38:19 CDT 2016

Yes thankfully the previous owner labelled everything.  The cards seem to be in great physical shape, however the motherboard does have a bit of corrosion here and there.
PSU checked out ok in preliminary testing.
The CPU card appears to be set up for Flex.. the expected jumper is cut and it looks like the 6810 onboard is bypassed. If I read Michael Holley's guide right that just means I need my first RAM board configured as '0'.. but that was the case already.. not sure why that would ever not be the case.
Baud rate seems to be set correctly.. at least by the hand written label next to the dip switches on both cards.

Sent from my Samsung device

-------- Original message --------
From: william degnan <billdegnan at gmail.com> 
Date: 2016-08-04  5:19 AM  (GMT-08:00) 
To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> 
Subject: Re: SWTPC 6800 

On Aug 4, 2016 2:54 AM, "jim stephens" <jwsmail at jwsss.com> wrote:
> On 8/3/2016 10:58 PM, Brad H wrote:
>>      Thought I would post this here in case it reaches eyes my forum
posts don't.  So I finally got my hands on a SWTPC 6800!
>> This machine is chock full of boards.. 4 ram boards, the cpu card (with
SWTBUG ROM), MP-S, MP-C serial cards, a floppy controller, some little
custom board, a sound card.. etc.
>> This presents some challenges obviously, since the machine has been
altered from stock it could be tricky getting it running.
>> Before I had it stripped down, I tried powering up as is (i pulled the
older MP-C card and put MP-S in slot 1).  This produced little except for a
string of random characters that would repeat every time I hit reset,
exactly the same number.
>> I tried stripping it down to CPU card, MP-S, and the RAM board
designated as '0'.. but all I get at the terminal end is a single random
character on power up.
>> I then thought I'd try my luck putting the CPU card in my working MSI
system (taking out its card).  Nope.
>> Now, because my CPU card has been modified to accomodate SWTBUG and
possibly something else, I'm not sure if it'll even work in a stripped down
config.  Not sure about the interplay between boards.
>> Anyway.. if anyone has any thoughts to point me in the right direction
I'd be most appreciative.  Ultimately I'd like to get this beast working
with my CT1024 terminals.
>> Brad
> I saw an SWTPC booth registered at VCF West, maybe you should drop by.
I'll look in and see what they have and maybe they can help too.
> Only SWTPC gizmo I have is one of their audio amplifiers somewhere in the
pile.  Picked up at TRW Swap Meet.
> Thanks
> jim

You need to start with the power supply.   Verify it's ok. Then work
through each card's jumpers to see how they are set.  For example the MP-S
has baud rate setting options, and the card can be used with a Teletype or
RS232 terminal.  1200 is max baud.

If you're getting a consistent but garbled output to the screen did you
confirm the baud rate you're using matches the MP-S jumpers?

All of this is well documented online, Mike Holley has a step by step set
up on his site.  A few years ago I retyped the entire code listing of TSC
BASIC which can be downloaded into  bare bones SWTPC 6800

More information about the cctalk mailing list