Yaesu FT-857 Technical Supplement page 18

Alignment
Power Amplifier Adjustment (Lot 60 ~)
HF/50 MHz Idling Current Adjustment
1. Connect the 50-Ohm dummy load to the HF/50 MHz
antenna jack.
2. Tune the transceiver to any HF band, or to the 50 MHz
band.
3. Disconnect the wire jumper from TP3025 and TP3026
on the PA Unit, then connect the ammeter between
TP3025 (+) and TP3026 (–).
4. Turn VR3001 fully counterclockwise.
5. Press the PTT, and adjust VR3001 for an indication of
600 mA (±10 mA) on the ammeter.
6. Disconnect the ammeter, and re-connect TP3025 and
TP3026 using the wire jumper.
V/UHF Idling Current Adjustment
1. Connect the 50-Ohm dummy load to the 144/430 MHz
antenna jack.
2. Tune the transceiver to the 430 MHz band.
3. Disconnect the wire jumper from TP3025 and TP3026
on the PA Unit, then connect the ammeter between
TP3025 (+) and TP3026 (–).
4. Turn VR3002 fully counterclockwise.
5. Press the PTT, and adjust VR3002 for an indication of
1000 mA (±50 mA) on the ammeter.
6. Disconnect the ammeter, and re-connect TP3025 and
TP3026 using the wire jumper.
TP3003
VR3001
TC3001
18
Directional Coupler Balance Adjustment
1. Connect the 50-Ohm dummy load to the HF/50 MHz
2. Tune the transceiver to 28 MHz band in the CW mode,
3. Press the PTT, and adjust TC3002 for minimum indi-
4. Connect the 50-Ohm dummy load and wattmeter to
5. Tune the transceiver to 439.995 MHz in the CW mode.
6. Press the PTT, and adjust VR3003 for minimum indi-
7. Leave the transceiver on 439.995 MHz band and key
8. Adjust TC3001 for maximum indication on the watt-
PA Unit ( Lot 60 ~ ) Alignment Points
antenna jack.
and connect the DC voltmeter to TP3003 on the PA
Unit.
cation on the DC voltmeter.
the 144/430 MHz antenna jack
cation on the DC voltmeter.
the transceiver.
meter.
TP3025
TP3026
TC3002
VR3003