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TUCoPS :: Radio :: icr70002.txt

Icom ICR7000 mods

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.

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