[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.

> 

> 

> 

> 

> 

> 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

>> 

>> --

>> Coco mailing list

>> Coco at maltedmedia.com

>> http://five.pairlist.net/mailman/listinfo/coco 

> 

> 

> --

> Coco mailing list

> Coco at maltedmedia.com

> http://five.pairlist.net/mailman/listinfo/coco