TM 11-6125-261-30
Table 3-6. Troubleshooting Chart-Continued
Corrective
Checks
Correct
Posible
Test
Malfunction
reading
cause
action
conditions
c. Replace A24U29 if
c. Use oscilloscope
c. A noisy d.c. voltage
signal is incorrect.
similar to A2 within .5v
probe at A22E12.
of ground.
Check to assure that the
Use voltmeter at pin 2 of
17V, 01 V.
4. No output or Vin is 28 V dc 01V. A24Q16 failed.
output lead of A24 Q16 is
A2T2.
very low output Iin not more than 10
not shorted to ground.
of OB and OC Amps. No load.
Replace A24 Q16.
together.
5.
a. Check the oscillator
a Sine wave at least
a. Use oscilloscope to
a. No output or Vin + 28 V dc. No
transistor and replace if
4Vpp 400 Hz.
check signals A3, A4,
failure.
very low output load.
required. Check the
and A5.
of one phase only
inductor for an open or
(any phase).
short. The inductor
should measure about 50
ohms from each side to
the center ground
connection. Replace as
required.
b. If signal A9 remains
b. Signal A9 per figure
b. Pulser
b. Use oscilloscope to
b. No output or
him check signals A6
three.
inoperative.
check for signal A9 of
very low output
and A7. If A6 is not
the defective phase.
of one phase
present but A7 is okay,
only.
replace diodes in full
wave rectifier. If A7 is
high and remains high,
check the overcurrent
ampifier transistor
(A22Q112 for OA) with
a VOM. Replace as
required.
a. If the feedback
a. For OA, signal All
a. Vin + 18 V dc. a. Feed back
a. Check for signal Al
6. Output
as shown. For OB and
signals are not present,
at A22BE(OA). Check
No had. Iin less
loop open.
voltage of any
OC, a modified
repair the wiring if
for feedback signals
phase does not
than 10 amps.
halfwave rectified sine
required. Check the
at A21E6 for OB and
CAUTION
regulate. Output
A24R29 and R32 for
wave.
A21 E16 for OC.
exceeds 125 V ac.
To trouble-shoot,
OA. Check A24T5 and
decrease Vin until
U24 for OB and A24T6
the bad Vout is
and U24 for OC.
125 V ac or less.
Replace components as
Continuous high
required.
Vout will cause
failure of the
output tuning
capacitors.
b. Vout error
b. Refer to Table 3-1.
b. 6.2 V dc 0.2 V dc.
b. Refer to the
detector defective
Check the emitter of
discussion in Chapter 2
or oscillator
A22Q103.
Section 2, paragraph 2-
control defective.
7 and 2-8. The analog
signals should react as
stated. Replace the error
detector (OA-A22Q103)
as required.
c. Pulser shorted
c. Check to see that
c. Check signal A10 for
c. As indicated by the
signal A9 is as required.
the defective phase.
waveform A1O in figure
If A9 is good, check the
3-1.
signal at the base of
three high current pulser
switches. This signal
should resemble A10 in
form. If this signal is
good, at least one of the
3-18
