[Coco] OT: SWTPC

[Joel Ewy]

On 12/08/2013 11:58 AM, Ron Bihler wrote:
> With all the talk in regards to the SWTPC and os9 I have dug my system 
> out and have been attempting to get it going again.  I have done the 
> ritual cleaning of the contacts and looking over the boards for 
> issue.  I am not getting the startup prompt or any output from the 
> rs232 port. With a scope I see signs that it has reset, and shortly 
> after reset I see activity on the buss.  My suspicion is a problem 
> with the Memory board and the system is cycling looking for the start 
> of memory location.   I am also not 100% sure the jumpers on the CPU 
> board and Memory board are set correct.  The CPU board has the eprom 
> and some memory, not sure if this should configured to be included or 
> now.  The Tanner memory board has a way to exclude memory.
> The system did work once,  but it went south and I have never gotten 
> it up an running since.  I pull it out and end up putting away again 
> after I get frustrated (Grin)  It came from a wet environment and it's 
> very dry in Colorado so after a few months of working the contacts 
> looks really bad.  I have cleaned and cleaned, it will tease me once 
> in a while and output the prompt but then as quickly goes away.  After 
> the many times of messing with it, the jumpers may not be correct or I 
> have damaged another component.
>
>  Is there someone of the group who is good at this computers. Might be 
> able to swap out boards?
>
> Thanks
> Ron Bihler

I have a bunch of SWTPC parts that I'm also (very slowly) trying to put 
back in working order.  I've put up a few blog posts about it: 
http://8littlebits.wordpress.com/category/swtpc/

I'm not sure how practical it would be to actually swap boards, but we 
could certainly compare notes.  Just know that at the moment the SWTPC 
is not terribly high on my priority list, though it doesn't take much to 
reignite interest.  But the things are so dang big, it takes some effort 
to clear workbench space to set them up and work on them.  I'd really 
like to get DriveWire running on the SWTPC.  I have made an OS-9 LI boot 
disk from the emulator disk image collection.  At least 1 of the 6809 
CPU boards I have has the DAT circuitry, so it should be capable of 
running Level II in principle, but I haven't come across any evidence 
that LII was ever available for the SWTPC.  (I wonder how similar the 
GIMIX DAT was...)

First step is to get the CPU boar(s) talking to the terminal again, 
which may just be a matter of cleaning contacts, and then get enough 
memory boardage to boot OS-9 and check out the FDC.

Which CPU and memory boards do you have?  I got mine as far as running 
the ROM monitor once.

JCE
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