Yaesu FT-840 Service Manual page 15

SSB Modulator Balance
D With the transceiver tuned to 14.200.0 MHz,
USB mode, connect a 50-Q dummy load
antenqa jack, and
MIC
0 Set the
control fully ccw (min.), RF PWR
control fully cw (max.). Key the transmitter,
and adjust VR 1008 for minimum indication on
RF
the millivoltmeter.
AM Output Adjust
D Tune the transceiver to 14.200.0 MHz, AM
mode, and connect the wattmeter and 50-Q
dummy load to the antenna jack.
RF PWR
D Set the control fully cw (max.) and the
MIC
control fully ccw (min.). Next key the
transmitter and (with no modulation) adjust
VR 1020 for 25 watts on the wattmeter.
&
Side-Tone Beep Level
D Connect a AF millivoltmeter across a 4-Q
resistor or speaker connected to the EXT-SPKR
jack.
D Connect the CW key to the KEY jack, adjust the
RF PWR control fully ccw (min.), then key the
transceiver.
D AdjustVR2001 on the Local Unit for 150 mV
± 20 mV.
Speech Processor Check
D Set VR 1012 to the 12 o'clock position, the MIC
gain to the 10 o'clock position and the
control fully clockwise (max.). Inject a 1-kHz
TC4001
FT-840 Technical Supplement
to
RF
millivoltmeter to J1005.
RF PWR
LPF Unit Alignment Diagram
signal from the AF generator to the microphone
jack (pin 8).
D With the wattmc e ter and dummy load connected
the
to the antenna jack, tune to 14.200.0 MHz, USB
mode, key the transmitter and adjust the SG
level for an ALC meter indication of S-3.
D Press the
meter indication of S-5 or more.
CW Semi-Beak-in Delay Time
D Adjust VR1015 to the 12 o'clock position,
then set the RF PWR control fully ccw (min.),
and select CW mode.
D Repeatedly key and un-key the transmitter, ad­
justing VR1015 for a delay time of approxi­
mately 1 second following key-release.
Transmitter Carrier Point
(LSB)
D Temporarily jumper TP2003 t o c h a s s i s
ground, then connect the AF signal generator
to the MIC jack, and adjust the output level for
3 mV.
D Select USB mode, tum the transceiver off, then
press and hold the SSB & FM buttons together
while turning the transceiver on again (this
places the transceiver in the carr i er-point set­
ting mode, next select LSB mode for the first
carrier point adjustment step).
D (a) Set the MIC control to the 12 o'clock posi­
tion and RF PWR control fully cw (max).
D (b) Key the transmitter, and adjust the
level to where the ALC meter indication de­
flects no further.
Alignmen t
PROC
button, and confirm an ALC
AF
SG
3-5