[Coco] eBay MPI Heads Up

[K. Pruitt]

Okay, here's the low down on my initial testing...

The MPI itself works just fine.

With the switch in the Coco 1/2 mode position, the Coco 3 will not see the 
disk controller and will boot in to extended color basic.
This is expected behavior according to the Marty Goodman article that 
Stephen provided. I assume it will see the disk controller when running a 
Coco 1/2 but I haven't tested that yet (have to find the TV adapter thingie 
to hook it to a TV).

With the switch in the Coco 3 mode position, the disk controller is 
recognized and I get the Disk Extended Basic screen as normal.

I can boot in to SDC-DOS and everything seems to work fine, but attempting 
to boot in to NitrOS9 or OS9 via the SDC results in the computer hanging at 
the shell prompt. My 26-3124 had this same issue with the SDC when trying to 
boot either flavor of OS9.

I intended to examine it with a loop before testing it, but what the heck 
just plug it in and hope the magic smoke doesn't escape. So now, with magic 
smoke still contained, I am going to examine Marty's board with a loop. 
Whoever repaired the traces on this board is very good with a soldering gun. 
So kudos to whomever it was.

If the board can safely be removed (more examination is required to make 
that determination) I will photograph the component side of the board and 
post them.

By the way, this is serial number 005684. It's a grand-pappy even among the 
grey MPIs.

----- Original Message ----- 
From: "K. Pruitt"
Sent: Friday, May 29, 2015 4:30 PM
Subject: Re: [Coco] eBay MPI Heads Up


> Here's a picture of the innards.
>
> https://www.dropbox.com/s/i9xwgxtwwibbs6l/DSC01405.JPG?oref=e
>
> As suspected, it contains a mod to allow it to be used with a Coco 1/2 or 
> a Coco 3.
>
> The board was apparently manufactured by Marty Goodman as it has his name 
> on the board. Some of the traces show signs of repair.  I'll take a loop 
> to it later prior to testing. I have no clue as to which position of the 
> switch is which. But there may be detailed information about Marty's mod 
> on the Internet. I seem to recall seeing it somewhere. If not on the 'net 
> then in Rainbow.
>
> Thanks Bill.  Much appreciated.
>
>