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Icom ICR7000 mods
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ICR7000.2
Date: 19 Sep 88 22:03:02 Z
Subject: R7000 DOUBLE MEM. MOD
Double the Memory Capacity of Your R7000?
Bob Parnass, AJ9S
The ICOM R7000 appears to use a uPD446C, 16K static RAM
chip, for storing 99 memory channels. By looking at
the pinout of this chip (IC8 on the Logic Unit) in my
service manual, it appears that ICOM is only using 1/2
its memory capacity. Address lead A10 (pin 19) is sol-
dered to a ground pad.
To double the number of memory channels in the R7000 to
198, is looks like one could "lift" pin 19 of IC8, and
connect it to the center of a SPDT switch. One pole of
the switch should be grounded, the other connected to
the proper +V through a 10,000 ohm resistor.
Another challenge would be finding a place on the R7000
to put the added "Memory Bank" switch. Perhaps one
could use the Noise Blanker switch, and just leave the
NB on at all times.
I don't have time to try this experiment, and would be
interested in hearing results from any enterprising
hobbyist willing to try this.
CONTINUED IN FILE ICR7000.3
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