[Coco] CoCo 64k RAM upgrade on Ebay

[Bruce W. Calkins]

Yes, those look like 16 K chips, which would have been removed for an 
upgrade.



I see them all as having a 8040517 label.





From;

http://users.digitalindigo.net/~techno/coco2.html



"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."



Bruce W.



=============================================


----- 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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