Re: 6702 chip

From: Mike Naberezny <>
Date: Thu, 10 May 2012 12:36:41 -0700
Message-ID: <>
Hi Olaf,

On 5/10/12 5:44 AM, Rhialto wrote:
> Worse, I tried to run the Waterloo software, after transfering it from
> disk images that worked fine in VICE, and that didn't work... (the
> results were, after loading, either a return to the menu, or a hang). I
> also tried the No6702 versions with the same result!?.

The Waterloo software gets loaded into the expansion RAM.  When there is bad 
RAM, what you described is the symptom.  You can check the expansion RAM by 
writing a quick program on the 6502 side to exercise it; even BASIC is fine 
for this but it will take a while to run.

This problem is usually seen on the 3-board version where the expansion RAM is 
4116 DRAMs.  I have repaired several SuperPETs where one or more 4116s went 
bad.  The combo board uses 4164s.


Mike Naberezny (

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Received on 2012-05-10 20:00:15

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