Icom IC-R71A Instruction Manual page 25

compensating oven heater and a crystal unit. By replacing
the original crystal unit with this unit, the total frequency
stability of the set will be improved.
The specifications of the crystal unit itself are as follows:
-
Oscillation frequency: 30.72MHz +10ppm
Stability: +0.5ppm in the range of —30°C ~ +60°C
8-5-2 ASSEMBLY PROCEDURE =
1. Turn the receiver left-side up.
2. Unscrew the six screws retaining the PLL board, then
turn the board over so that foil side can be seen.
3. Remove the solder of the original crystal unit terminal
pins and grounding lead on the foil of the PLL board, by
a de-soldering braid, then take off the crystal unit and
grounding lead.
4. The location for the high-stability crystal unit is shown
in the photo. The holes for the terminal leads of the
unit are predrilled. If the holes are filled with solder,
remove the solder with a de-soldering braid.
Unscrew the six screws at ''\"'
Installation position
for this unit.
Be sure to orient the unit so that the crystal and heater
terminal leads (indicated on the bottom of the unit) are
the same direction as shown on the photo.
Insert the unit flush with the board, bend the leads flush
with foil side of the board and solder them in.
Jumper
the lands
with the
supplied
wire with
insulating
tube.
<— Remove solder.
O Lead holes for the new unit.
5. Trim the leads even with the solder points.
6. Jumper the lands of the foil indicated in the photo by
using the supplied wire with insulating tube. At this
time, take care not to make short with other lands of the
foil.
7. This completes the installation. Replace the PLL board,
and the top and bottom covers.
8-5-3 OPERATION
No adjustment is required and the unit improves the fre-
quency stability of the set as follows:
Frequency Stability of IC-R71 with CR-64:
Less than +50Hz after switch on 1 min to 60 mins, and less
than +10Hz after 1 hour at normal room temperature. Less
than +100Hz in the range of —10°C ~ +60°C.
8-6 INTERFACE UNIT IC-EX309
When the IC-EX309 is installed, the operating frequency,
mode, memory write, memory read etc. of the set can be
controlled by a personal computer through the ICOM
CT-10 optional interface unit.
8-6-1 ASSEMBLY PROCEDURE
1. Turn the receiver upside down, and remove the option
unit installation plate by unscrewing the retaining screws.
2. Remove the "PLATE B" attached to the rear panel by
unscrewing two screws. These screws will be used later.
3. Pass the accessory socket cable (the end attached 9-pin
and 8-pin connectors) through the hole which was
attached the PLATE B before, from the outside of the
chassis. Then attach the accessory socket by using the
screws described above.
4. Insert the 9-pin connector to J10 and the 8-pin con-
nector to J15 of the LOGIC unit respectively.
Insert 9-pin connector to J10
Insert 8-pin connector to J15.
= BF