Sect.
N
Page
11
TABLE 4-2. TROUBLE SHOOTING CHART (CONT'D)
Symptom
Possible Cause and/or Remedy
Meter. indication is equally erratic on all ranges.
Trouble in power supply (see paragraph 4-9).
Tubes V2, V3, V4 and/or
V5
defective.
Crystal diode
cm
and/or CR2 defective.
Capacitor C2 may be shorted or leaky.
NOisy R23.
Meter indication more on one
range than on other
Leaky
0.051
Ilf coupling capacitor in range switch.
ranges.
Replace defective unit.
Meter painter "beats" when power line frequency
Trouble in power supply (see paragraph 4-9).
(usually
60
cps) or a harmonic thereof is ap-
plied to INPUT.
Heater-cathode leakage in VI, V2, V3, V4 or V5.
Replace one tube at a time.
Readjust heater
dc voltage after final tube selections have been
made.
Recalibrate instrument (paragraph 4-7).
Open bypass or decoupling capacitor anywhere in
instrument.
Repeated adjustment to increase amplifier gain
Trouble in power
supply (sp.e
paragraph
4_9).
needed to maintain calibration.
Tubes
VI,
V2, V3, V4 and/or V5 defective.
Crystal diodes CRI and/or CR2 defective.
Capacitors C32, C33, and/or C34 defective.
Meter pointer strikes peg sharply when switching
Tubes VI, V2, and/or
V5
are the most probable
ranges, particularly when switching from
O.
3-
tube defects.
However, V3 and/or V4 maybe
to I-volt range with no input.
defective.
Delayed secondary switching transient particularly
The only disadvantage of this is a slight increase
when switching from
the
0 . 3- to the I-volt range
of instrument recovery time when switching
with no input.
ranges.
Most probably caused by a gassy tube
for VI, V2, and/or VS.
May also be V 3 andl
or V4.
A similar symptom may exist between any two ranges
when any of C7 through C12 capacitors are
leaky.
Microphonics
With DB VOLTS switch on I-volt range, apply a
(Mechanical shock causes excessive fluctuation
I-volt
(400
to
1000
cps) signal to INPtrr.
Llghtly
of voltmeter reading.)
tap lower right corner of meter case.
H
meter
p01nter pins Sharply against right hand stop,
tubes VI andlor V2 are microphonic.
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