Icom IC-R8500 instruction manual CR-293 HIGH STABILITY CRYSTAL UNIT

12 OPTIONAL INSTALLATIONS

■CR-293HIGH 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 HIGH STABILITY CRYSTAL UNIT is available. It has a stability of ±0.5 ppm.

➀Remove the bottom cover as shown on p. 37.

➁Remove 6 screws from the metal plate, then remove the metal plate and shield cover.

➂Remove 10 screws from the PLL unit, then open the unit to expose the bottom.

➃Unsolder the feet of the internal crystal unit, then remove it.

➄Place the CR-293 in the space available as shown in the diagram, then solder its feet into place (6 points).

➅Adjust the reference frequency using a frequency counter.

➆Replace the ground spring to its original position.

➇Return 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.

Ground spring

Metal plate

Shield cover

PLL unit

CR-293

Internal crystal unit

PLL unit

39