Kenwood TR-7400A Service Manual page 31

Symptom
(3) Defective deflection at RF
meter (under normal power
supply.
(4) Excessive power range.
(5) Hi- Low switchover malfunc-
tion.
(6) Consumption current devi-
ating from 4A (approx.) at
144 MHz without antenna
connection.
(7) Large spurious.
(8) Transmitlreceive change-
6
over malfunction
(9)
Modulation impossible.
(10) Tone squelch
(in TX setting)
.
(1 1) Tone burst malfunction.
lmproper adjustment in protection circuit.
TR defective in final driver stage.
Abnormal voltage in AVR (2SD235).
Improper adjustment for trimmer in pre-driver stage.
Antenna SWR defective.
lmproper adjustment for VR1 in PA unit.
A: When TX unit is normal.
lmproper adjustment for TC1
)
B: When TX unit has a band.
lmproper adjustment for TC1
lmproper adjustment for VR61
printed circuit board.
Poor contact in Hi-Low switch.
lmproper adjustment for VR5 in TX unit.
01 2 defective in TX unit.
04 defective in PA unit.
lmproper adjustment for VR3 in PA unit.
Defective in TX unit.
A: For near-by spurious.
lmproper adjustment for L7, L8 in TX unit.
lmproper adjutsment for L11
lmproper adjustment for VR61
printed circuit board.
B: For harmonics spurious.
lmproper adjustment for TC1
'
Microswitch broken.
Poor contact MIC terminal
at
1
Relay defective (RL101).
MIC element defective.
Poor contact at MIC terminal.
SW of main body and 071 of printed circuit board defective.
01 defective in TX unit.
lmproper adjustment for VRI, VR5 in TX unit (in the case
of insufficient modulation).
insertion of printed circuit board of active filter
in RX unit
Active filter defective.
01 1 defective in RX unit.
Note: If modulation degree is improper, adjust
of RF unit.
-
a- 06 08 defective in TX unit or piezo tuning fork broken.
lmproper adjustment for VR4 or trouble in C41, D6 in the
case of abnormal time constant.
Cause
-
TC4 in PA unit.
-
TC4 in TX unit.
-
VR63 in main-body choke
-
L14 and VR3 in TX unit.
-
VR63 in main-body choke
-
TC4 in PA unit.
with VR31
it
Remedy
Check
Readjustment
Check
Readjustment
Readjustment
Readjustment
Readjustment
Replacement
Readjustment
Replacement
Replacement
Readjustment
Readjustment
Readjustment
Readjustment
Readjustment
Readjustment
Replacement
Check
Replacement
Replacement
Check
Replacement
Replacement
I
Readjustment
Check
Replacement
Replacement
Replacement
Readjustment
or replacement