Reference Oscillator & Pll Vcv; Transmitters - Yaesu FT-5100 Technical Supplement

perature be held constant between 20 and 30
°C (68 - 86 °F). If the transceiver is brought
into the shop from hot or cold air it should be
allowed some time for equalization with the
environment before alignment.
Whenever possible, alignments should be
made with oscillator shields and circuit boards
firmly affixed in place. Also, the test equip­
ment must be thoroughly warmed up before
beginning.
Most alignment procedures call for tuning
the transceiver to the high or low band edge,
or to band center. The actual frequency differs
between different versions, so the technician
should make sure of the band limits of each set
to be aligned before beginning.
Note:
Signal levels in dB referred to in the
alignment procedure are based on 0 dBµ
dBµV.
Reference Oscillator & PLL VCV
Connect the 50-ohm dummy load to the
antenna connector and maintain the supply
voltage at 13.6 V for all steps.
Reference Oscillator
D
Couple the frequency counter to sample the
RF
output.
D
Key the transmitter and adjust TC1001 on
the Main Unit to match the display to the
counter frequency (within 100 Hz).
VHF PLL VCV (Varactor Control Voltage)
D
Connect the negative lead of the DC volt­
meter to chassis ground, and the positive
lead to the side of C1258 nearest VR1006 on
the chip-only side of the Main Unit.
D
Set the transceiver to 144.000 MHz, and ad­
just T801 through the hole in the VHF VCO
housing on the leaded-component side of
the Main Unit for 1.0 V on the voltmeter
while receiving.
D
Key the transmitter while adjusting T802
VHF
(also in the VCO housing) for 1.5 V on
the voltmeter.
UHF PLL VCV Check (no adjustment)
Connect the positive lead of the DC voltme­
D
ter to the solder pad shown in the diagram
2-2
Servicing
of the leaded-component side of the Main
Unit.
D
Tune to 430.000 MHz (432.000 MHz in ver­
sion D) and confirm the VCV
and 4.5 V while receiving, and between 2.5
and 5.5 V while transmitting.

Transmitters

For all of these procedures, connect the test
equipment as shown below, and refer to the
diagrams on pages 5-5 and 5-6 for test point
locations.
VHF Power Output
D
Tune to band center (for the version being
aligned), and press the
sary, to select high power output.
D
Key the transmitter and adjust VR102 on
=
0.5 the 144-MHz PS Unit for 50 watts on the
wattmeter (use care not to exceed 60 watts
during the alignment).
D
Press the
key the transmitter, and confirm 3 to 6 watts
on the wattmeter.
UHF Power Output
D
Perform the same steps as above for VHF,
adjusting VR1003 on the Main Unit for 35
watts on the wattmeter (do not exceed
watts).
50-olvn
Dummy
Load
Coupler
Freq
Counter
Deviation
Meter
Oscilloscope
AF
Milivoltmeter
Transmitter Alignment Setup
is
LOW
button, if neces­
LOW
button to select low power,
lnhne
Wattmeter
Power Supply
Technical Supplement
FT- 5100
between 1.5
42
13.BV DC
AF
Generator
AF
Milivoltmeter