[Coco] CoCo 2 with Random Characters on Screen at Power Up

[Brian Blake]

How did you swap the CPU?

Once when I swapped out a 6809 for a 6309 I had a similar problem, which 
had two causes. I accidentally cut a trace under the socket when I was 
removing the 6809. I didn't find it until I started investigating why 
the CoCo's screen looked like an ASCII jigsaw puzzle. Once I fixed that, 
I still had the problem - which turned out to be a bad CPU. Either 
caused by the cut trace or it was just a bad CPU - it happens.

On 1/16/2014 2:31 PM, Danny Amborn wrote:
> I have a CoCo 2 model 26-3027 that shows random characters on the
> screen at power up.  I bought this computer knowing it had issues but
> when I received it initially it was working fine for a few days before
> acting up.
>
> I replaced the RAM and the CPU so far.  I thought for sure it was the
> CPU because it looked like it had a burn mark in the center but it
> must have just been some sort of blemish but it does the same thing.
> Since this is a 26-3027 so most of the chips are socketed, lucky me. I
> also have a 26-3026 which is the same model just without the extended
> basic.  I am willing to swap all the socketed chips but was wondering
> if anyone knows which chips to start swapping first?
>
> --
>
> Dan Amborn
> slackware64 at embarqmail.com
>
> --
> Coco mailing list
> Coco at maltedmedia.com
> http://five.pairlist.net/mailman/listinfo/coco


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