Cr-293 High Stability Crystal Unit - Icom IC-R8500 Instruction Manual

12
OPTIONAL INSTALLATIONS
CR-293
HIGH STABILITY CRYSTAL UNIT
A temperature-compensating crystal with a stability of
± 3 ppm is built-in to the receiver. For more demand-
ing operation, the CR-293
is available. It has a stability of ± 0.5 ppm.
UNIT
Remove the bottom cover as shown on p. 37.
Remove 6 screws from the metal plate, then
remove the metal plate and shield cover.
Remove 10 screws from the PLL unit, then open
the unit to expose the bottom.
Unsolder the feet of the internal crystal unit, then
remove it.
Place the CR-293 in the space available as shown
in the diagram, then solder its feet into place (6
points).
Adjust the reference frequency using a frequency
counter.
Replace the ground spring to its original position.
Return the shield cover, metal plate and bottom
cover to their original positions.
NOTE: The CR-293 is an oven-type crystal unit,
and the specified frequency stability described
above is guaranteed 1 min. after power ON.
39
HIGH STABILITY CRYSTAL
Ground
spring
Metal plate
Shield
cover
PLL unit
CR-293
Internal
crystal
unit
PLL unit