[Coco] coco3 won't boot

Dave Philipsen dave at davebiz.com
Wed Oct 12 14:47:26 EDT 2016


Not only might you break the socket if you don't use a PLCC removal tool, you could also bend the pins.  A PLCC extraction tool typically pulls up on opposite corners of the chip with equal force such that the chip is pulled straight up without tilting.  If you live in a pretty dry climate you might want to try something else other than paper just because of static build up (as Mark said...ESD precautions). I suppose you could go in the bathroom and turn the shower on hot to get a little more humidity in the air to neutralize static charges. 

Another idea would be to do the same thing with one of those white buffer boards that women use to polish their nails. I'm not talking about the ones that look like sandpaper.  The white ones are very fine and are used to actually polish the surface of the nail to a high gloss.

Dave Philipsen

> On Oct 12, 2016, at 9:54 AM, Mark Marlette <mmarlette at frontiernet.net> wrote:
> 
> 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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