Table 3-6. Troubleshooting Chart -Continued
Malfunction
Test
Posible
Correct
Corrective
Checks
conditions
cause
reading
action
transistors if either
one of a pair is faulty.
Inspect for burned
resistors A22R136,
A21R107 or R7. Failure
of any of these
resistors indicates
failure of the high
power sections for
that phase. Repair as
required.
b. Transistors not burned. b. Signals should duplicate b. If one phase has bad
signals but the drive
sync.
cable from the pulser at Noise level is lower and transistors check good,
A14E4, E5, and E6.
disconnect the wire a
from terminals 4 and 5
clean and square.
Check signals at A22
Q110, Q1l1, A21Q5, Q9,
of the associated
Q105, Q109.
interstage transformer
(OA-A2T3, OB-A2T2
and OC-A2T4). If
signals A13 and A14
return to normal, the
high power switch
transistors have failed. If
the signal remains
distorted, the interstate
The high power
transistors may also be
bad if the transformer is
burned out. Replace
components as required.
C. Phase locking
c. Two channel Oscilloscopec. Compare the phase c. Check "or broken wires
and repair as required.
required. Disconnect the relationship of A3, A4,
circuit open.
and A5 two phases at a Check for an open
pulser as above.
ding of the inductor
time. Use A5 as the
scope sync. Vp-p may
secondary. It should
vary but phase
read about 100 ohms.
relationships must be
Replace connector if the
secondary is open.
stable.
d. Replace burned
d . Remove the A27 and A8
d. Output tuning
capacitors. Replace the
modules and inspect for
capacitors open
A44 filter if there is any
burned capacitors.
or shorted.
evidence of black gum.
Inspect the A44 filter for
To check for open
any leakage of black
capacitors, disconnect
U.
2 of all three phases.
with a capacitor checker.
be 11 mfd for each
phase. (One mfd is
internal to the A44 filter.
O. Check A22Q101,
a m17.5 V l V.
a. Vcc regulator
3. NO output all 3 V is 28 V.dc 1V.
Q102, CR102, CR103.
+ lead of A22C105.
Iin is less than 100
failed
phases.
Replace as required.
ma.
b. +17 volts normal. +2
b. Overload does not
b. OverCurrent
exist but A22E13 equals
Volts after overload
A22E13.
timer failure.
2 Volts. Check A22Q113,
foldback only.
Unit is in
A114, and Q115 with a
permanent
VOM and replace as
foldback.
required.
3-17