[comp.sys.cbm] C64 thermal

gjs@mtgzz.att.com (g.j.shevchuk) (10/04/88)

I'd like to get some ideas on the cause of the problem I've been having
the last several months with my 64.  When turned on, it works fine for
maybe an hour or so, and then at some point the screen image starts
breaking up in various spots with speckles, and within 15 - 30 seconds
the whole screen is just a random array of multi-colored speckles.  It
almost looks like a crystallization process.  The system is then locked up,
not responding to any keyboard action, but will operate ok again after
a half hour or so of rest.  Has anyone seen this or know the likely cause
of it?  My unit is the basic C64, probably 4 years old or so.

George Shevchuk
mtgzz!gjs

edson@jpl-devvax.JPL.NASA.GOV (Edson Smith) (10/06/88)

In article <4567@mtgzz.att.com> gjs@mtgzz.att.com (g.j.shevchuk) writes:
>I'd like to get some ideas on the cause of the problem I've been having
>the last several months with my 64.  When turned on, it works fine for
>maybe an hour or so, and then at some point the screen image starts
>breaking up in various spots with speckles, and within 15 - 30 seconds
>the whole screen is just a random array of multi-colored speckles.
>
>George Shevchuk
>mtgzz!gjs

I had this problem too, and my local C-64 repairman was able to trace
it to a bad interface on the board where the power supply plugs into 
the machine.  The power supply itself was fine.  Apparently, once the
machine warmed up to a certain temperature, something started to lose
it, resulting in the random color pattern described.  It cost me about
$35 to get it fixed.  Sorry I can't be more specific, but hey, I don't
do hardware!

Edson Smith  OAO/JPL  edson@devvax.jpl.nasa.gov  ames!elroy!jpl-devvax!edson

Geoffrey.Welsh@isishq.FIDONET.ORG (Geoffrey Welsh) (10/07/88)

 > From: gjs@mtgzz.att.com (g.j.shevchuk)
 > Organization: AT&T, Middletown NJ
 > Message-ID: <4567@mtgzz.att.com>
 > the last several months with my 64.  When turned on, it
 > works fine for
 > maybe an hour or so, and then at some point the screen
 > image starts
 > breaking up in various spots with speckles, and within
 > 15 - 30 seconds
 > the whole screen is just a random array of multi-colored
 > speckles.  It
 > almost looks like a crystallization process.  The system
 > is then locked up,
 > not responding to any keyboard action, but will operate
 > ok again after
 > a half hour or so of rest.  Has anyone seen this or know
 > the likely cause
 
   It sounds like your DRAM chips are flaky.


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asmodeus@tree.UUCP (Jonathan Ballard) (10/16/88)

In article <237.235431A2@isishq.FIDONET.ORG>, Geoffrey.Welsh@isishq.FIDONET.ORG (Geoffrey Welsh) writes:
> 
[stuff deleted]
>  
>    It sounds like your DRAM chips are flaky.
> 
> 

I wouldn't want to say that at first!  
-------------------------------------

Try the power supply.  I put iIce pack on mine it it won't freeze up.  
If I have no ice pack then my system start surging and the video gets messed
up and finally it will lock up.   I have found out a power pack problem does
also look like a video chip(s) problem symtoms.
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