Correction
Probable trouble
Symptom
Step
Replace C3.
Bias supply filter capacitor
C3 short-circuited.
Replace T2.
T r a n s f o r m e r T2 secondary
winding 2628 open.
-
SCREEN VOLTS meter M6 does Screen supply tube V3
Replace V3.
6
defective.
not indicate.
Check meter M6 and replace if
SCREEN VOLTS meter M6
necessary.
defective.
Replace C4.
Screen supply filter capacitor
C4 short-circuited.
Replace defective resistor or poten-
Screen voltage multiplier re-
sistor R56 or SCREEN volt-
tiometer.
age potentiometer R54 open.
Replace T2.
Transformer T2 secondary
winding 1525 open.
Check meter M4 and replace if
S I G N A L m e t e r M 4 d o e s n o t SIGNAL meter M4 defective.
7
defective.
indicate.
Replace defective resistor or poten-
Signal voltage divider resis-
t o r R 4 7 , R49, R50 or SIG-
tiometer.
NAL-V.R. potentiometer
R46A open.
Replace T2.
Transformer T2 secondary
winding 29, 30 open.
8
Check switch S3 and replace if
No change in voltage indication or PLATE-SCREEN RANGE
switch S3 defective.
necessary.
incorrect indication on PLATE
meter M5 and SCREEN VOLTS
meter M6 when PLATE-SCREEN
RANGE switch S3 is rotated.
FILAMENT VOLTS meter M1 in- Tube under test defective
Check filament continuity of tube
9
under test.
dicates but tube under test does
not warm up.
FIL- or FIL+ Selectors
Replace S6, S7, or S11 as necessary.
switch S6 and S7 or SHORT
TEST switch S11 defective.
10
With GRID SELECTORS switch
FIL CONT. SHORT lamp 12
Replace lamp 12 if necessary.
defective.
S8 in position B, PLATE SELEC-
TORS switch S15 in position A,
Check switch S11 and replace if
and all other SELECTORS.
SHORT TEST switch S11
defective.
necessary.
switch at 0, and with the A.
and B- electrical clips short-cir-
Check wiring and repair as neces-
cuited, FIL. CONT. SHORT lamp Wiring in short test circuit
defective.
sary.
12 does not light in any position
of SHORT TEST switch S11.
Replace defective resistor,
Voltage-divider resistor R60
or bias supply bleeder resis-
tor R35 open.
Adjust R45 so that the index mark-
PLATE potentiometer R45 in-
correctly adjusted.
ing on the knob lines up exactly
with the index marking on the
panel.
11
With tube tester adjusted for trans. PERCENT QUALITY meter
Check meter M3 and replace if
M3 defective.
defective.
conductance (G,,,) test and
PRESS TO TEST P4 switch
Replace C2.
S19 in locked position, PER- Quality meter damping ca-
CENT QUALITY meter M3 does
pacitor C2 short-circuited.
not give proper indication.
Shunt resistor R30, R31, R40 , Replace defective resistor or poten-
or R42 or GM CENTERING
tiometer.
potentiometer R44 or
AGO 1428A
21
