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|  Symptom
Probable
trouble
Correction
Step
2
Meter indications are present when Defective if. step attenuator
With operating power applied and
AT201 (fig. 66).
SIGNAL ATTENUATOR DB switch
SIGNAL ATTENUATOR DB switch
at 20, check for -150-volt ener-
is rotated to 0 SUBST. ONLY, but
pointer cannot be zeroed at 20,
gizing potential from protruding
40, 60, and 80, even with GAIN
terminal of feedthru capacitor C2
control set fully clockwise.
to chassis ground. If no voltage is
present, relay K2 will be inoper-
ative. Check continuity of wire
lead from C2 to terminal 15 of
connector P201 (fig. 64). Repair
c o n n e c t i o n s if necessary.
Remove cover from if. step atten-
uator and remove operating power.
Check for continuity from feedthru
capacitior C2 to chassis ground. rf
i n f i n i t e resistance is indicated,
suspect R7 and/or coil of relay K2
for open circuit. Replace defec-
tive component.
With operating power removed,
c h e c k precision resistors R1
through R5 for values indicated on
schematic diagram (fig. 25),
within +1% tolerance. Replace
defective components.
With SIGNAL ATTENUATOR DB
3
Meter indications are present when Defective relay K1 in if. step
switch at positions 40, 60, or 80,
attenuator AT201 (fig. 66).
SIGNAL ATTENUATOR DB switch
check for 150-volt B- energizing
is rotatad to 0 SUBST. ONLY and
p o t e n t i a l from protruding termi-
to 20, but pointer cannot be
nal of feedthru capacitor Cl to
I zeroed at 40, 60, and 80.
chassis ground. If no voltage is
present, relay K1 will be inoper-
ative. Check continuity of wire
lead from Cl to terminal 14 of
connector P201 (fig. 64). Repair
c o n n e c t i o n s if necessary.
Check for continuity from feedthru
capacitor C1 to chassis ground.
If infinite resistance is indicated,
suspect R6 and/or coil of relay
K1 for open circuit. Replace
defective Component.
Meter indications are present at
Faulty contacts on band switch
4
Remove operating power. Rotate
20-70 mc of band switch, but
band switch to 70-220 mc and
S201B (fig. 65).
cannot be obtained at 70-220 mc.
check for continuity between wiper
(W) of switch S201B and primary
winding (ungrounded terminal) of
T203. Repair or replace defective
switch.
Faulty contacts on band switch
Reapply operating power, with band
S201A.
switch at 70-220 mc. Check for
150-volt B+ power at plates of
V204, V205 (pin 5), and V206A
(pin 6) to chassis ground. No B+
voltage at plates indicates defect
between contacts Z2 and 23 on
switch S201A. Repair switch.
Defect in 150-volt B+ line to
Check R238, the primary winding of
V206A (Fig. 65).
T204, and R238. Replace defec-
tive component.
Defect in 150-volt B+ line to V205
Check for open in R237, R239, and
inductor L213. Replace defective
component.
Check for open in R224, R22S, or
Defect in 150-volt B+ line to V204
L211. Replace defective compo-
nent.
127
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