[Coco] CoCo 3 RAM upgrade question

Blake Patterson blakespot at gmail.com
Wed Feb 1 15:22:48 EST 2012

So, part of the haul of CoCo items I got in this recent package was a somewhat hacked up CoCo 3 bare motherboard with a 512K RAM expansion on it. I removed it and performed the upgrade to my main CoCo 3. 


To figure out the drill I looked over at Cloud9 for instructions on their SIMM board. It said to pull the 4 existing RAM chips and clip the upper C64 cap and the lower C65 cap. I noticed on the CoCo 3 that this upgrade came from that the C65 (lower) cap was clipped, but not the C66 (upper) cap. This is contrary to the Cloud9 instructions, but perhaps it's a different drill for different boards?

The system powers up fine with the upgrade in it, but still I get just a few blocks read through DriveWire before it just sits there on almost every OS9 boot I perform using "DOS" command. Boisy thought maybe I was running out of RAM -- was hoping that things would be working now.

Do I need to clip that upper cap? Is the RAM not fully recognized? 



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