trs-80 model II trouble--problem solved..and follow-up
ethan.dicks at gmail.com
Wed Dec 16 15:42:59 CST 2009
On Wed, Dec 16, 2009 at 3:21 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
>> Thanks to everyone's advice. You were all right (as was my original
>> suspicion)...that it was the video memory.
> Well done!/ Repairing this old hardware can be fun, and it's a great
> feeling when it works again (or at least is is for me).
>> So...a couple of questions:
>> 1) How can I get just 1 2114...
> Get more 2114s :-). In my experience it's one of the most unreliable
> chips there is, to the extend that I've replaced them in just about
> everything I've got that uses 2114s at some time or another.
I second that. I've replaced many 2114s over the years. One
commercial board I worked on in the past (the COMBOARD-I), had a field
of 32 chips. Memory failures were one of the most common reasons
boards ended up back on the bench. I learned to cleanly unsolder
parts from 4-layer boards because of them (clip the leads at the IC
body, then extract the pins one-by-one). I got lots of practice.
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