[Coco] CoCo 1 -> CoCo 2 conversion

[KnudsenMJ at aol.com]

In a message dated 10/29/04 11:28:42 PM Eastern Daylight Time, 
rtaylor at bayou.com writes:

> I plan to leave the 6809 as-is, but I might replace the PIAs with 68B21EP's 
>  one day.  The DRAMs are socketed, as well.  I'm thinking I can drop some 
>  64k x 1-bit chips in there and maybe get 32k out of them without doing any 
>  64k hacks to the board.

If it's old enough to have all socketed chips (betcha even the "TI" (TTL) 
chips are by Motorola), it's probably like mine, and requires a NOR gate hack 
(about three wires) to run 6K.  No piggybacking needed, IIRC.

I did find my good old graycase One in the attic, so can take a closer look 
if you want.  But for $4.95, that One should already be in your room anyway :-)
 
>  Also, the 6847 chip is socketed, which tempts me to replace it with the 
one 
>  from a Korean CoCo 2 so I can get the true lowercase and other little 
extra 
>  video effects.  I'm basically wanting to give this thing the innards of a 
>  CoCo 2 and just see how good it can play the part.

That lower case is well worth the effort.  I installed an aftermarket LC 
adapter in mine, with a switch on the side (or was that Bob Rosen's Coco I'm 
remembering?).  It works great, but the updated VDG chip is a lot cleaner -- if you 
can get one without solder globs all over its legs :-)
--Mike K.