Yaesu FC-757AT, Инструкция по эксплуатации

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Variable Capacitor Presetting
This procedure involves a combination of mechan­
ical and electrical adjustments that determines the
position-sensing parameters used by the CPU to
control TUNE and LOAD capacitors VC 201 and
VC 202 via the resistance of sensor potentiometers
VR0, and VR02 on the motor-driven shafts. VR 1os
and VR106 on the CPU Unit are used to preset the
sensor voltages for the TUNE and LOAD controls,
respectively, after the mechanical settings have
been made, and all setscrews tightened.
1. Loosen the setscrews in the ny Ion shaft
couplers on the sides of the shafts of VC 201 ,
VC 202, VR 0, and VR02, using the 1.5 mm
Allen wrench.
2. Set VC 201 and VC 202 to their fully meshed
positions, and tighten the two associated
setscrews on their shafts.
3. Set VR 01 and VR02 both fully counterclock­
wise (viewed from the rear, shaft side), and
tighten the two associated setscrews on their
shafts.
4. Press the TUNE
"1>"
button and observe the
position of VC 201 when it stops. If this is not
the point of minimum capacitance, adjust
VR10s on the CPU Unit (the motor will move
the capacitor automatically).
5. Press the TUNE
"<l"
button and note the
position of VC 201 when it again stops. If this
is not the point of maximum capacitance
(fully meshed plates), loosen the shaft coupler
and reposition VC 201
•
Then tighten the set­
screw again and repeat steps 4 and 5.
6.
Follow the same procedure as in steps 4 and
5 to adjust LOAD capacitor VC 202, using
VR106 on the CPU Unit to set the point of
minimum capacitance.
Backup Battery Replacement
To determine whether the lithium backup battery
needs to be replaced, measure the DC voltage
between the top of the battery (exposed side) and
ground. If this is 2.0 volts or less, the battery
should be replaced. Use a Sony type C R2025-WT 1
or Sanyo CR 2025. New battery voltage is 3 volts.
Use care not to short circuit either new or old
batteries.
1. Switch the POWER switch off, and set back­
up switch S 101 (as shown below) on the CPU
Unit off. Remove the five screws affixing the
CPU Unit.
2. Unsolder the terminals of the old battery, and
install the new battery in the same manner.
Then replace the CPU Unit and its five screws.
3. Set the POWER switch ON first, and then
reset S 101 to the left (on) position. DO NOT
TURN THE BACKUP SWITCH ON FIR ST.
All data previously stored has now been erased, so
remember to reset the antenna selector switches
for the proper bands before rematching.
CPU UNIT
FRONT
ON
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