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|  (3) Tuning unit 1.
Probable
trouble
Symptom
Correction
Step
Defective connection at terminal
Check soldering of coaxial cable on
1
Tuning unit 1 interconnected
A2 on connector P1 (fig. 56).
tuning unit side of P1, terminal
through test harness to main unit;
A2. Lift curved spring cover off
POWER switch at ON; IMPULSE
right angle terminal A2 with
GENERATOR DB ABOVE lV/
s c r e w d r i v e r to repair connection.
MC switch at ON; impulse gener-
If either center conductor within
ator ouput control fully clock-
terminal A2 or dielectric insula-
wise; but no meter indication on
tion is cracked or broken, replace
any positions of MEGACYCLES
complete connector P1.
band switch.
Poor or no connection between
Check for secure electrical contact
between P9 and J2. If this does not
subminiature connector plug
P9, at harness end of wires
remedy trouble, disconnect tuning
running from receptacle P1, to
unit connector P1 and check
connector J2 on detector and
resistance from each terminal to
e l e c t r o m e t e r assembly Al (fig.
chassis ground for correspoxui-
56) .
ence with measurements shown in
Poor or no connection between
Check to see that if. output selector
protruding coaxial connector
plug P7 makes secure mechanical
plug P7 on if. output selector
and electrical connection with
mating jack J1.
jack J1 on detector and elec-
t r o m e t e r assembly (fig. 56).
Faulty 455- or 1,600-kc if. am-
Troubleshoot each if. amplifier
plifier (fig. 56).
subassembly by signal substitu-
tion (para 71). Check if. ampli-
fiers V4 through V8.
Warning: cleaninq compound is
flammable and its fumes areo toxic.
DO not use it near flame; provide
adequate ventilatione
Clean terminals on tuner segments
Fualty contacts between termi-
nals 1 through 19 on each tuner
and on spring wiper contacts with
segment with corresponding
Cleaning Compound (Federal
spring wiper contacts on rf
stock no. 7930-395-9542) or with
a crocus cloth. Work from top of
58) .
tuning unit (fig. 56), and rotate
the band switch to each of its six
positions so that 19 terminals on
e a c h tuner segment are accessi-
ble for cleaning.
Check for defective rf amplifier
Faulty rf tuner section (fig. 56)
V1, mixer V2, and oscillator
V3 in tube tester. Replace defec-
tive tube. If low indication is
observed on panel-mounted test
s e t meter after tube replace-
ment, realignment of the rf tuner
section will be required (para
Check for continuity of contacta in
Faulty band stitch S1 (fig. 56) --
2
O n s c a l e meter indication are ob-
each switch position by referring
served with MEGACYCLES band
to switch legend on tuning unit 1
switch at band 1 (.15-.36 mc)
schematic diagram (fig. 99).
band 3 (.87-2.1 mc), but cannot
Repair or replace S1 if necessary.
be obtained in bands 2, 4, 5,
Check for secure connection of con-
Defective cable connections to
and 6.
nector plug P3 with mating jack J2
1 , 6 0 0 - k c if. amplifier, or
on if. step attenuator AT1 sub-
defective 1,600-kc if. amplifiel
assembly (fig. 60). Also check for
secure connection of connector
plug P5 with mating jack J4 on if.
output selector subassembly (fig.
118
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