Heathkit SB-401 Assembly Manual page 143

1. Check voltages and wiring of tube sockets
VIO and VII.
2. Resistor RI7 open.
3. Feedthrough capacitor C67 not connected
to lug 2 of coil RFC9.
4. Check loading circuits.
5. Check wiring of Band switch.
6. Check antenna relay circuit (RL2).
7. Band switch incorrectly wired or posrtioned,
No RF output.
1. Insufficient drive to final tubes V10 and VII.
2. Check bypass capacitor wiring to driver
coils and Band switch.
3. Check wiring in final amplifier compart-
ment.
Neutralizing not possible.
No RF voltage at pin 5
of tube sockets VIO and V11.
1.
Shorted coaxial cable from tube socket V5.
2.
Band switch incorrectly wired or positioned.
3. Coils improperly wired.
4. Bandpass filter improperly installed.
5.
Heterodyne oscillator not functioning.
6.
Check voltages and wiring of tube sockets
V4 and V5.
7. Relay RLI improperly
wired,
8. Bias not removed from pin 1 of tube socket
V5.
9. Pin 2 foil of tube socket V5 shorted to
ground.
10. Cable to SB-301 not connected or FREQ
CONTROL switch not in LOCKED position.
No RF voltage at pin
2 of driver
tube
socket (6CL6) V9.
1. Defective crystal diodes.
2.
Balanced modulator transformer improperly
installed.
3. Carrier Null control open or. shorted.
4. Level control not counterclockwise.
Carrier Null does not
null properly.
~------
1. Open choke, RFC4.
2. Open chokes, RFC5 and RFC6.
3. Check voltages and wiring of tube sockets
V9, VIO, and VII.
4. Check wiring of Band switch.
5. Check wiring of coils.
6. Check wiring of relay RLI.
7. Bias not removed from pin 2 of tube socket
V9.
8. 8.645 MHz trap improperly adjusted C303.
9. Cable to SB-30l not connected (Transceive
only).
TRANSMITTER DIFFICULTY
Page 119