[Coco] PAL Coco 1/2 schematics/timings

[Aaron Banerjee]

I believe it was the "285" board that was the same as the "F" board.   
I upgraded one once to 64K.  Aside from the chips, I only remember  
having to clip a few capacitors in the memory area.

Regarding 4K "D" boards, I've got one that's been upgraded.  It is  
quite flaky, but I'm not sure if that's just because it's old, or that  
you have to dink with them in order to use the 32/64 K and that the  
"surgery" was only 95% successful.  I'd like to keep it running --  
especially since it still has the "4K RAM" sticker on it....

      - Aaron

On Sep 18, 2010, at 8:29 AM, Bruce W. Calkins wrote:

>> Mark,
>>
>> I have Schematics / Service Manuals for most of the European PAL  
>> boards (starting with one of the first 4K PAL CoCo 1 from 1980/81  
>> or so (serial #3xx, wasn't that named an "F-Board"?)
> <snip>
>>
>> Best regards,
>> Torsten
>
> No, the "F" or 283 board was the last version of the CoCo 1 and had  
> a lower limit of 16k, with hardware provisions for 64k accessable  
> with OS-9.  4k would have been a "D" or earlier board.  The "E"  
> board had no provisions for 4k, but required added wireing for 64k.   
> Few "C" or earlier boards were released for sale, so data on them is  
> limited.
>
> Bruce W.
>
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