[Coco] Another MPI on fleabay

[Bill Pierce]

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
 

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-----Original Message-----
From: Gene Heskett <gheskett at wdtv.com>
To: coco <coco at maltedmedia.com>
Sent: Wed, Mar 11, 2015 7:10 pm
Subject: Re: [Coco] Another MPI on fleabay




On Wednesday 11 March 2015 16:54:15 Bill Pierce via Coco wrote:
> I looked at
the pics on ebay and the jack is near the AV outputs. My
> jack is near the
power switch (opposite end). Gene has the 2 meg
> upgrde and could say where the
jack is located on his as they may be
> different. Power is needed on both ends
as there's a memory board over
> the 512k upgrade (left from font) and a dat
board over the 6809 (right
> from front), so the PS could enter either side and
be convenient. Mine
> has a jumper wire going from one board to the other. Tony
D, may have
> changed the lo0cation of the jack for some reason. Then it may not
be
> a 1 or 2 meg upgrade at all.... :-(

Bil: My 2 meg T.D. kit, uses 1 meg
CMOS simm modules, and I believe it 
was installed prior to my converting it all
to run from an old XT power 
supply. AFAIK, this kit didn't need an extra
supply.

I'd go down and verify that by looking at it, but I've about beat me to

death today, and do not have another trip down and back up the basement 
steps
left in me.  Getting old is NOT for wimps.

I'll try and look to see if I
carried it downstairs when I ran across the 
peach envelope with the docs that I
just ran across 5 or 6 days ago 
while searching for old bank statements in this
midden heap.  Just found 
it, about 3 feet away.  Title is "Inside DISTO's 2 -
meg Kit", so this 
isn't the install docs.  The circuit theory is heavy with
Tony blowing 
his own horn like he is the only one that knows how to use an

oscilloscope. But the text and schematic seem to agree. The vcc supply 
comes
up from the motherboard, on the same pin a 512K card would use.  
There is not,
in the text or in the schematic, any mention of an 
external power supply.  So I
don't think the 2-meg kit needed more than 
the coco 3 can supply on its own.


Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of
liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed
Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>

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