[TenTec] CorsairII obsolescence - MCU copying

[Jerry Haigwood]

Steve,
   Almost All Digital Electronics now makes a Display which will work with
the Corsair II.  Jim Warner, WA9Z, has successfully installed one the
displays into his Corsair II.  You can obtain one of the displays by
contacting Neil the owner of AADE by email at neil at aade.com and asking for
the Corsair II display.  The back lit display fits into the Corsair with a
little metal work.  If the 68705P3 processor is getting hard to find, the
AADE display is an alternative way to go.
Jerry W5JH


-----Original Message-----
From: tentec-bounces at contesting.com [mailto:tentec-bounces at contesting.com]
On Behalf Of Steve Hunt
Sent: Tuesday, August 02, 2011 3:21 AM
To: Discussion of Ten-Tec Equipment
Subject: [TenTec] CorsairII obsolescence - MCU copying

Recently I've been idly thinking about how I might keep my CorsairIIs 
running in the event of failure of the MCU on the Logic Board. I realise 
the preferred approach might well be to replace most of the 
functionality with a modern PIC frequency-counter/display module. 
However, I was interested to come across a series of articles on the Web 
about how to extract data from a "good" 68705P3 and copy it into 
another. The technique is a bit time consuming - it involves forcing the 
reference MCU into the verification stage of a programming cycle, 
offering it all possible Hex values of every byte, and noting by 
differences of bus timing which byte verifies successfully. Sounds 
involved, but at least one guy has automated the process and produced a 
stand-alone 68705P3 copier:

http://matthieu.benoit.free.fr/144.htm

The programmer/copier also allows you to dump the reference contents 
from RAM to a PC; it would then be easy and fast to replicate the part.

I wonder if anyone readers have tried something similar? I also wonder 
if it's worth asking the author if he would be prepared to use his 
copier to provide a dump of the contents of a CorsairII MCU?

73,
Steve G3TXQ
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