Kenwood TR-7400A - Page 31

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