[Coco] Upgraded MPIs and Harware incompatability

[Mike Pepe]

I think the CoCo Max hi-res pack uses $FF90- that's one device that 
won't work properly with a modded MPI.

-Mike

Bruce W. Calkins wrote:

> The first suggestion of a PAL switcher to switch between CoCo 3 use and CoCo

> 1/2 use seems to be Marty Goodman in The Rainbow on January 1987 starting on

> page 98.  Here he does not say that the upgraded pack does not work on CoCo

> 1 &2s, but rather that some 3ed party hardware will not work with the

> upgraded MPI.  This is the earliest reference to a PAL switcher I have found

> so far.

> ----------------------------------------------------------------------

> In CoCo Consultations, The Rainbow, April 1987 a PAL switcher is addressed.

> This one is a bit vague as to the reason for the need to revert to the old

> PAL for use with the CoCo 1/2

> ----------------------------------------------------------------------------

> 

> I don't have time to research this much further now.  Suffice to say there

> was some confusion as to the needs for the upgrade in the first place, and

> it's affect on older equipment.

> 

> If Mark M. states the upgraded MPIs work fine with the CoCo 1 and 2, I can't

> argue it.

> 

> Bruce W.

> 

>