[Coco] Another MPI on fleabay

[Gene Heskett]

On Wednesday 11 March 2015 20:15:19 Bill Pierce via Coco wrote:
> Gene, the 1-megger was about two years before the 2-meg so the
> technology was better with the 2 meg, and chips needed less power
> (probably less chips as well). All 1megs I've seen (4-5) had external
> PS's. I remember the ads even stating an external PS was included. My
> 1-meg has a 2nd 512k board almost identical to the 1st 512k (same
> amount of memory chips) mounted directly into the 512k expansion, then
> the original 512k plugs into that. Only one wire connects the memory
> boards to the dat board on the CPU.. a power wire. I just checked my
> 1-meg PS and it's a 9v supply. The docs I found state the same.
>
>
> Bill Pierce
> "Today is a good day... I woke up" - Ritchie Havens

That makes perfect sense Bill.  That 512k board was also dram, but with 
older, bigger transistors, and IIRC was not CMOS technology. The power 
draw for cmos stuff pretty much scales with the clock frequency, and a 
coco sure doesn't push that very far even with 1.79Mhz clock in the 
coco3.

This is where I might, for those who can afford it, promote Marks half 
meg of static "Triad" ram .  I'd fully expect to shine an IR thermometer 
on the pass transistor in the coco3's power supply, and see it running 
20F cooler just by swapping the ram boards.

I'm guessing of course, but I'd imagine Mark can put some hard figures to 
that which would be more accurate than my SWAG's.

Mark?

[...]

Cheers, Gene Heskett
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