[Coco] CoCo 1 64K upgrade failed

[Frank Swygert]

You may have damaged one or more of the 64K chips, or it may have been bad before you touched it. In any case, you can go back to 16K. The caps filter noise, but it should work without them. 

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Date: Thu, 25 Sep 2008 21:08:50 -0500
From: Ryan Pritchard <coconut at pritchard.ca>

I followed the instructions for the 32K / 64K upgrade that I was  
provided.  I compared all 3 to 4 versions including a 32K only one.   
The nice part was the 32K only upgrade was the same steps for the 64K  
upgrade sans some extra jumper wires.

I only got as far as having desoldered my 64K x 1 DRAM from my extra  
Apple //e 80 Column Card, and following the steps up to the end of the  
32K upgrade instructions.

The CoCo does not boot.  I have cut all eight of the correct  
capacitors C31, C35, C45, C48, C61, C64, C67, C70, moved all the  
jumpers to the 32K setting, and tried both the LOW and the HIGH back  
jumper positions.

I think I may have burnt out the 64K x 1 DRAMs.  I don't know what  
else it could be and since I removed all eight caps breaking a couple  
in the process I can't return to the 16K system  :( .

I guess my options are find a good set of 64K x 1 DRAM, or cut my  
losses and pick up a CoCo 3 from Cloud 9.

Currently kinda frustrating because the Extended Color Basic ROM I got  
confirmed the FDC works.

-- 
Frank Swygert
Publisher, "American Motors Cars" 
Magazine (AMC)
For all AMC enthusiasts
http://farna.home.att.net/AMC.html
(free download available!)