UNIT
WILL NOT TURN ON
|
1.
|
Broken/defective
DC Power cable. |
|
2.
|
Fuse
blown. Be sure you check for the cause. |
|
3.
|
Defective
power switch. |
|
4.
|
Defective
wires or poor soldering in power supply circuit. |
NO SOUND RECEIVED
|
1.
|
Defective
RF circuit in receiver. |
|
2.
|
Defective
Noise Blanker. |
|
3.
|
Defective
audio power IC, IC5. Check Voltage at pin 6 of IC5; if approximately
6V, problem is not with this IC. |
|
4.
|
Squelch
is "ON" all the time. If voltage at Base of TR12 is approx.
0V with Squelch Control in fully counterclockwise, problem is not
with squelch circuit. Defective TR12. |
|
5.
|
Check
whether the transceiver's signal strength meter deflects when a signal
(27 MHz carrier with 1 kHz, 30% modulation, 100µV level) is
applied to antenna.
a. The meter indicates "S-9".
You can assume that antenna through IF stage are OK.
NO AM . . . . Checks should be made on Detector (D16 and 17) ANL circuit
(D18), TR24 and AF stage (TR11, TR12, VR501 and IC5).
NO SSB BUT AM OK . . . . Check frequency and level on TP5, if no signal,
checks should be made on X-tals and TR24.
NO SSB . . . . Checks should be made on Detector, TR11, T R12 and
AF stage, VR501 and IC5.
b. No deflecting of meter.
Checks should be made on RF stage (TR13 and TR14), IF stage (TR15,
TR16, TR17 and TR18) or
AGC circuit (TP8, 07, D8 and IC1). Or trouble may be in PLL circuit.
Check frequency on TP3; if
it is as listed in the Table, problem is not with PLL circuit. |
|
6.
|
Defective
AGC circuit. |
|
7.
|
Defective
PLL circuit. |
|
8.
|
Defective
antenna connector. |
NO
NOISE
|
1.
|
Broken
or bad contact in microphone connector and/or push-to-talk switch. |
|
2.
|
Defective
RX power circuit. |
|
3.
|
Defective RX audio circuit. |
|
4.
|
Defective
PLL circuit and/or channel switch. |
|
5.
|
Defective
squelch. |
|
6.
|
Defective
PA-CB switch. |
NO
TRANSMISSION
|
1.
|
Broken
or bad contact in microphone connector and/or push-to-talk switch. |
|
2.
|
Broken
or bad contact in antenna connector. |
|
3.
|
Defect
in power supply. |
|
4.
|
Defect
in PLL and/or Carrier Oscillator (Improper adjustment). |
|
5.
|
Inoperative
microphone amplifier and/or balanced modulator in SSB mode. |
|
6.
|
Check
the frequency at TP3; carrier oscillation may have stopped; if no
carrier, check TR24, D27, 28, 29 and X2. |
|
7.
|
Carrier
is OK, but no TX; check the frequency at TP3. If not same as listed
in Frequency Table, PILL circuit defective. If OK, check IC3, 6, TR35,
538 and 539. |
|
8.
|
If
no TX on SSB modes and no modulation on AM mode, Mic amplifier or
ALC/AMC section is defective. Check TR36, 37, 38 and 544. |
NO MODULATION
|
1.
|
Defective
microphone. |
|
2.
|
Defective
microphone connector. |
|
3.
|
Inoperative
microphone amplifier, (both AM and SS8 modes.) |
NO NOISE BLANKER
OPERATION
With N8 Switch ON, apply a 27 MHz carrier signal to antenna. Then check
DC voltage at TP1 varying the
carrier signal front 1µV to 100µV.
|
1.
|
When
TR1 voltage stays on and does not vary: Check TR1, 2, 3, 4, 6, D1
and D2. |
|
2.
|
When
TP1 voltage varies from dV to approx. 2V. Check TR6 and 7. |
|
3.
|
If
(A) and (B) are alright, L2 may be misaligned; go to alignment procedure
for adjusting L2. |
CHANNEL LED DOES
NOT LIGHT
When a specific segment fails to light, it is probable there is an open-circuit
in the LED display or bad contact in the channel selector switch.
|