[Coco] coco3 won't boot

[Mark Marlette]

Robert,
Probably a GIME that needs it's pins cleaned.
Using a PLCC extraction tool, remove and with a clean piece of printer paper, wipe in the direction of the J leaded pin on the GIME. Paper is on a flat surface GIME is in your hand. ESD precautions  should also be observed. You will see a path of pins on the paper. Wipe a couple times, rotate, repeat until all sides are cleaned, reinsert. Observing pin 1, points left from front of computer.
I would start there. Do not attempt to remove the GIME without the PLCC tool, the risk of fracturing the socket is too high.
If that doesn't work, then try the memory, CPU. That is the general path to repair. Most are fixed with these steps, if not then we will have to get a bit tougher with it.
Regards, Mark Marlette
 http://www.cloud9tech.com
mark at cloud9tech.com



      From: Robert Hermanek <rhermanek at centurytel.net>
 To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com> 
 Sent: Wednesday, October 12, 2016 9:44 AM
 Subject: [Coco] coco3 won't boot
   
(Warning:  I have no electronics knowledge, and no time in the near 
future to learn!)  I have a coco3 that has been working for thirty 
years.  It has recently stopped booting.  The bare coco3, no MPI, no 
carts, the warranty sticker was intact, so about as stock as you can 
get.  On power up it displays a blank green screen, exactly as if it is 
about to display the extended basic banner, but it hangs at this stage.  
The only thing I've done is opened the case to see if any components 
looked damaged, and gave the socketed chips a little push to make sure 
they were fully inserted, but no help there.

Anything else simple I should be checking?  I know there is no shortage 
of "poor dead coco" threads on the list, but thought I'd ask anyway.  
Thanks in advance!

-RobertH

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