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TUCoPS :: Radio :: icr70001.txt

Icom ICR7000 mods


                Making the Modification

Accessing this circuit  board  is  not  difficult,  and
involves  the  same  steps  used  when  installing  the
optional Remote Controller or Speech units.

Use a towel to cover your work area to avoid scratching
the  R7000 cabinet.  Unplug the R7000 from the AC line,
and turn the radio  upside  down.   Remove  the  bottom
cover by removing the 12 screws holding it in place.

Remove the 4 screws holding what ICOM terms the "parti-
tion  panel".  Pictures on pages 32 and 34 of the R7000
Instruction Manual show  the  partition  panel.   After
removing  this  panel,  the component side of the LOGIC
UNIT circuit board is accessible.

Locate R18, a 270,000 ohm 1/8 watt resistor, near  con-
nector J5.  You may wish to remove plug P5 from J5 tem-
porarily if it gets in your way.   Carefully  solder  a
470,000  ohm  resistor  in parallel with R18.  I used a
1/4 watt resistor as it was the smallest on hand.

Reassemble the  radio,  connect  it  to  AC  power  and
antenna, and enjoy.

In the modified R7000, the scan and  search  rates  are
still  adjustable  using  the SCAN SPEED control.  With
the control turned fully clockwise (maximum speed), the
modified  R7000  scans  at about 13 channels/second and
won't miss weak signals.

 1. Perhaps the firmware polls the scan rate input port
    infrequently.  Another possibility is that the scanning
    pulses interrupt the processor, and the interrupt
    firmware is limited in its ability to process frequent

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