[Coco] Need help repairing a CoCo 2

[didier derny]

Thanks to all, 

 

The problem, came from the ram chips

I replaced them by 2  64kx4 chips and set the jumper to 64k

Now the machines starts and display:

 

“COLOR BASIC 1.3”

© 1984 TANDY

OK

 

But I don’t see any indication saying that now it has 64k

 

It’s strange but the chips are replacing the most often are ram chips

 

Thanks

 

--

didier

 

 

 

 

De : Francis Swygert [mailto:farna at att.net] 
Envoyé : jeudi 16 octobre 2014 14:20
À : coco at maltedmedia.com; didier at aida.org
Objet : re: Need help repairing a CoCo 2

 

First, go to www.maltedmedia.com <http://www.maltedmedia.com/>  and find the
CoCo List Archives, then find "Tandy's Little Wonder" and download that. It
has a quick repair guide that covers just about everything a hobbyist with
some soldering skills can repair with nothing more than a soldering iron and
multimeter. Has some schematics, but they didn't translate to PDF very well
and re hard to read. 

 

In your case, before I replaced the 6809 I'd pull the RAM chips then put
them back in the sockets. The pins get a little corrosion on them over time
and just pulling and putting back in will solve that issue. Your problem is
more likely to be a blown 6809, but won't hurt to try the easy way first. 

 

Frank Swygert
Publisher, "American Motors Cars" 
Magazine (AMC)
For all AMC enthusiasts
www.amc-mag.com