Correction
Probable trouble
Symptom
Step
SHUNT potentiometer R33
open.
Check switches S5 and S19 and re-
GM-SIGNAL RANGE switch
place if necessary.
S5 or PRESS TO TEST P4
switch S19 defective.
Replace defective resistor or poten-
With GM-SIGNAL RANGE switch Resistor R40 or R42 in trans-
12
tiometer.
S 5 in F position, PERCENT
conductance (G,,,) test net-
work or GM CENTERING
QUALITY meter M3 does not give
potentiometer R44 defective.
proper indication.
Check wiring and repair if defec-
With PRESS TO TEST P6 switch Wiring in grid circuit open
13
tive.
S21 depressed, indication on PER-
Replace defective resistor.
CENT QUALITY meter M3 drops Resistor R58 defective . . . . .
to zero.
Check wiring and repair if defect-
With tube tester adjusted for emis- Wiring in plate or meter cir-
14
ive.
cuit open.
sion test and PRESS TO TEST
P2 switch S17 depressed, PER-
CENT QUALITY meter M3 does
not indicate.
Replace defective resistor.
One of the current-limiting
resistors R19 through R25
in plate circuit defective.
Replace defective resistor or poten-
Shunt resistor R30, R31, R40,
tiometer.
R42, or GM CENTERING
potentiometer R44 defec-
tive.
Replace defective potentiometer.
With tube tester adjusted for vol- SHUNT potentiometer R33
15
tage-regulator test and PRESS
defective.
T O TEST P5 switch S20 de-
Replace defective potentiometer.
pressed, neither PECENT QUAL- SCREEN potentiometer R54
ITY meter M3 nor PLATE
or SIGNAL-V.R. potentio-
meter M5 indicate.
meter R46A defective.
Replace C4.
Screen supply filter capacitor
C4 short-circuited.
Check switch S4 and replace if
FUNCTION switch S4 defec-
necessary.
tive.
Replace defective potentiometer.
Operation of SIGNAL-V.R. con- SIGNAL-V.R.
16
potentiometer
trol R46 does not affect indica-
46B defective.
tion on PLATE meter M5.
Replace defective resistor.
Signal voltage divider resis-
tor R47, R49, or R50 defec-
tive.
Replace defective lamp.
With PRESS TO TEST PI switch FIL. CONT. SHORT lamp 12
17
S16 depressed and a tube known
defective.
Check switch S11 and replace if
to be good being tested, FIL.
necessary.
CONT. SHORT lamp 12 does not SHORT TEST switch S11 de-
light.
fective.
With tube tester adjusted for in- FUNCTION switch S4 defec-
Check switch S4 and replace if
18
necessary.
terelement leakage test, no deflec-
tive.
tion can be obtained on PLATE
Replace defective resistor.
meter M5 when there is leakage Multiplier resistor R38 defec-
between two or more elements of
tive.
tube under test.
and power transformer T2 windings are listed
18. Dc Resistances of Transformers T1 and T2
below. Measure the resistances with the trans-
former disconnected from the circuit.
The dc resistances of filament transformer T1
AGO 1428A
22
