Boot Loader for 3P+S on IMSAI

Win Heagy wheagy at
Tue Jan 10 12:12:36 CST 2017

Took a little digging but I found the thread where you were talking
about port 20/21.  I was able to configure the 3P+S card and run the
test from the solivant site successfully, but I'm not able to upload
basic.  I have a couple more things to try, including setting a small
upload delay as Bill suggests on his page.
However, I'm thinking that I may still have a configuration issue on
the 3P+S card.  But I think I'm getting close.


>The manual pretty much has the exact config for that port 20 is all you
>have to remember

>Bill Degnan
>twitter: billdeg
>On Jan 6, 2017 7:41 PM, "Win Heagy" <wheagy at> wrote:

> I have an IMSAI that I am restoring.  The basics appear to be working
> (front panel, CPU and RAM cards).  I have a Processor Tech, 3P+S card
> that is next on the list for testing.  I have the manual, but the card
> was not configured for RS-232...not sure what it was configured for
> but it doesn't match anything in the manual.  I plan to reconfigure it
> for RS-232. I'm trying to locate boot loader code for that board to
> allow serial uploading of files from a PC to the IMSAI? I have boot
> loader code for a 2SIO board on an Altair that I restored awhile back,
> and would like to find something similar for the 3P+S. I want to be
> able to toggle in a boot loader routine and then initiate an upload
> from the PC to IMSAI -- something similar to this
> (at 1:10s in) but with a 3P+S board on an IMSAI.
> Also, a picture of your RS-232 configured card and wiring of the edge
> connectors would be helpful to make sure I get things right.  Any help
> is appreciated.

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