[Coco] 2 MB upgrade in PAL coco3

[Bob Devries]

Hello, fellow coconuts.

I brought this topic up some time ago, with no resolution, so I'll present 
it again.

I have a Disto 2MB upgrade board here that I have tried to install into my 
Australian PAL coco3. Physical installation was fine, but... it just doesn't 
work.

I believe there was at one time a discussion regarding this problem on 
either Delphi or Compuserve. If anyone has the complete transcript of this, 
or has knowledge of the problem, I'd appreciate getting the information.

My guess is that it is a timing problem, or the clock signal used isn't 
correct somehow. The only change from the installation instructions is the 
connection of the clock signal. On the Australian Coco3, the master clock is 
supplied by a crystal oven; one of those small rectangular metal minidip 
devices with 4 pins. This signal connects to pins 2 (signal) and 3 (ground) 
of the GIME. I connected the upgrade clock signal to pin 2 of the GIME. The 
crystal oven's frequency is 28.475 MHz.

Can anyone help with this?

--
Regards, Bob Devries, Dalby, Queensland, Australia

Isaiah 50:4 The sovereign Lord has given me
the capacity to be his spokesman,
so that I know how to help the weary.

website: http://www.home.gil.com.au/~bdevasl
my blog: http://bdevries.invigorated.org/