TM 55-4920-244-14
Table 4-1. Troubleshooting-Continued
Malfunction
Probable cause
Corrective action
f. Defective resistor.
R34, R35, R36, R39, R41,
R42, and R43. Replace de-
fective components (para.
g. Defective switch SW-1.
g. Replace switch.
h. Incorrect reference voltage.
following components: C7,
C8, CR1, CR2, CR3, CR4,
CR5, CR6, CR7, R2, R3,
R13, R19, and T2. Replace
defective components (para.
a. Replace switch.
a. Defective switch SW-7.
14. No light beam in galvano-
b. Defective wiring or connec-
b. Repair or replace wiring
meters (GALVO-2).
tions.
c. Defective winding on trans-
former.
a. Replace galvanometers (para.
a. Defective galvanometers
15. Galvanometers (GALVO-2)
(GALVO-2).
cannot be set to zero with
mechanical zero knob.
16. No RPM indication with
RLY1. Replace if defective
switch SW-7 in RANGE
position.
b. Defective capacitor.
picators C3, C4A, C4B, and
C6. Replace defective com-
ponents (para.
c. Defective resistor.
sistors R6, R7, R8, R11,
R12, R17, R20, R21, R22,
and R37. Replace defective
components (para.
(6)).
Section Ill. REPAIR PROCEDURES
4-16. Voltage Regulator. (Figure 4-6).
4-15. General.
This section contains descriptions of com-
The voltage regulator (7) provides a
ponents and instructions for authorized field re-
means for regulating the voltage to the heaters
pair or replacement. Refer to Section IV for
in the heater probes. The voltage regulator is a
alignment that might be necessary before reas-
brush-type autotransformer. The voltage regula-
sembly.
tor has a 20-ampere rating with a voltage output
WARNING
variable from zero volts to approximately 130
percent of line (input) voltage available at the
Remove power from the tester before any
power inlet connector P-1.
disassembly procedure.
4-10
Change 1
