[Coco] 512 Upgrade

[Mark Marlette]

A special program could be written since they are 4 bit memory pairs 
for odd/even. Normal memory test programs would of course fail if all 
chips are not installed. Could only look at odd or even addresses and 
check the 8bits or whichever 4bits the memory is installed in.

Read the hardware and write the software...... :)

Mark
Cloud-9

Quoting Rick Ross <rickross at mail.rossprogramming.com>:

> Thanks for all the good idea's. I reseated all the chips on the mem
> board - same result - tried not pushing it down so far - same.
>
> My question.... does the board have to be fully populated to work? Can I
> cycle a couple banks thru to see if its just a bad chip?
>
> Also I plugged the 128 back in and it seems fine - c65 and c66 are still
> cut :)
>
>
> -----Original Message-----
> From: coco-bounces at maltedmedia.com [mailto:coco-bounces at maltedmedia.com]
> On Behalf Of Chester A Patterson
> Sent: Wednesday, August 09, 2006 1:05 PM
> To: CoCoList for Color Computer Enthusiasts
> Subject: RE: [Coco] 512 Upgrade
>
> Instead of cutting leads, my Disto upgrade was supplied with 1/4"
> plastic spacers (just lengths of wire shielding)
>
> -----Original Message-----
> From: Mark Marlette [mailto:mark at cloud9tech.com]
> Sent: Wednesday, August 09, 2006 8:54 AM
> To: coco at maltedmedia.com
> Subject: Re: [Coco] 512 Upgrade
>
>
> Stan brings up a good point about the length of the pins. On the CC3
> motherboard, some traces are under the connectors. So if the pins are
> long enough to make it to the MB, the two signals will short out and not
> function properly.
>
> As far as not cutting the caps from other posts. You are lucky and not
> the technical type to understand the logic behind, why you **should**.
>
> I just clip the long lead of the cap in both cases. That way if you want
> to reinstall the 128k, a simple solder connection is all that is needed.
>
> Mark
> Cloud-9
>
> Quoting Stan Blazejewski <stanblaz at netspace.net.au>:
>
>> G'day Rick,
>>
>> I remember when I upgraded to 512k many years ago that if I pushed the
>
>> memory board 'all the way home', it wouldn't work.  Whether the pins
>> were going to far & shorting something, I don't know, but I made small
>
>> spacers over a few pins  so that the pins would only go 3/4 way into
>> the headers & it worked reliably for many years afterwards  (& still
>> is).
>>
>> On Tue, 8 Aug 2006 12:22:43 -0400, you wrote:
>>
>>> Anyone who could help me I would be grateful :-)
>>>
>>>
>>>
>>> I have had a new Tandy 512 upgrade lying around and a perfectly good
>>> cc3 with 128k. so I figured why not make a 512 that doesn't work!
>>>
>>>
>>>
>>> I removed the existing chips and snipped c65 and c66 dropped the new
>>> 512 in....
>>>
>>>
>>>
>>> Turn it on and get green with no text. Removed 512 and put the old
>>> chips in - same thing a green with no text.
>>>
>>>
>>>
>>> I am quite sure this has been seen before, if so can you give me a
> clue?
>>>
>>>
>>>
>>> Thanks!
>>>
>>> Rick
>>>
>>>
>>>
>>>
>> --
>>
>> Australia isn't "down under", it's "off to one side"!
>>
>> stanblaz at netspace.net.au
>> www.cobracat.com (home of the Australian Cobra Catamaran)
>> http://groups.yahoo.com/group/cobra-cat/
>>
>> --
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>> Coco at maltedmedia.com
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>>
>
>
>
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