[Coco] CoCo 64k RAM upgrade on Ebay

[Rob Rosenbrock]

Also, this looks like a third party kit, whereas the chips are definitely Tandy stock.

On Dec 21, 2010, at 12:10 PM, Bruce W. Calkins wrote:

> Yes, those look like 16 K chips, which would have been removed for an upgrade.
> 
> 
> 
> I see them all as having a 8040517 label.
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> From;
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> http://users.digitalindigo.net/~techno/coco2.html
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> 
> 
> "26-3136
> 
> This machine is identical to the 26-3134, but with the Extended BASIC ROM factory-installed.
> 
> To upgrade the 26-3134 or 26-3136 to 64 KB of RAM, it is necessary to replace the eight 8040517 chips with 4164 chips of 200 ns or better access time, and to solder a wire between the two pads labeled J1. J1 is located next to IC7."
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> 
> 
> Bruce W.
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> 
> 
> =============================================
> 
> 
> ----- Original Message ----- From: "Rogelio Perea" <os9dude at gmail.com>
> To: <coco at maltedmedia.com>
> Sent: Tuesday, December 21, 2010 11:19 AM
> Subject: [Coco] CoCo 64k RAM upgrade on Ebay
> 
> 
>> Looks like the chips included in the following auction:
>> 
>> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320633337884
>> 
>> are the 16k ones *removed* after a CoCo 2 64k upgrade.
>> 
>> AFAIK the internal Radio Shack part number 8040517 defines a 16k x 1 RAM
>> chip, while the RS part 8040665 is the 64k x 1 chip.
>> 
>> Looking at the zoomed in chips image, the middle top one (with an apparent
>> smudge on the casing) appears to have p/n 8043517. Typo or photo illusion?
>> 
>> 
>> 
>> -- RP
>> 
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> 
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