TM 55-4920-401-13&P
( 2 8 ) T u r n P R O B E C O N T R O L f u l l y
3-5. Periodic Inspection. Every 180 days, perform
counterclockwise, turn MASTER power switch off,
and remove heater cable, junction box, and heater
probes from HEATER CABLE receptacle and
return to accessory case.
the checkout instructions of Chapter 4, Section II.
Section IV.
PREVENTIVE MAINTENANCE
3-6. General. T h e p r e v e n t i v e m a i n t e n a n ce
inspections will be recorded in accordance with
procedures outlined in the inspection worksheets
listed in paragraph 1-2. Each form covers a specific
inspection period, providing a system of progressive
preventive maintenance. These forms are available
through normal supply channels.
3-7. Cleaning. Clean the tester and accessories
with dry cleaning solvent (item 2, table 1-16).
3-8. Lubrication. As conditions warrant, remove
the two wheels from the accessory case, wipe off old
grease from wheel and axle bearing surfaces, and
apply a fresh coat of grease (item 3, table 1-16).
Maintenance.
3-9. Extreme Environmental
a. Cold. Provide best possible shelter to protect
tester from freezing rain, sleet, or snow.
b. Heat. Provide best possible shelter to protect
tester from direct rays of sun.
c. Dust and Sand. If possible, perform all
maintenance in a sheltered, well protected area.
(1) Reduce inspection and servicing intervals
and keep tester wiped clean.
(2) Keep tester under a protective cover.
d . H u m i d i t y . I f p o s s i b l e , p e r f o r m a l l
maintenance in a well ventilated or dry area.
Section V.
Operational Checkout
3-10. Performance Checks. The daily inspection
malfunction is followed by a list of probable causes.
procedures of paragraph 3-4b are sufficient for
The possible corrective action recommended is
checking the operation of the tester.
described opposite the probable case. The use of
conventional troubleshooting and corrective
3-11. Troubleshooting Data. Table 3-2 provides
methods will enable aviation unit maintenance
information useful in diagnosing and correcting
personnel to maintain the tester in operational
unsatisfactory operation of the tester. Each
readiness.
Section VI.
REPAIR AND REPLACEMENT OF AUTHORIZED PARTS
3-12. Replacement of Lamps.
a. Unscrew and remove lamp cap.
b. Pull lamp out of lamp socket.
c. Align pins of new lamp with holes in lamp
socket and insert lamp.
d. Reinstall lamp cap.
3-13. Replacement of Indicator Displays.
a. Use a phillips head screwdriver to remove
four screws from display bezel and remove bezel.
b. Use a flat bladed screwdriver to pry defective
display from display socket.
c. Insert new display in socket, orienting decimal
point at bottom of socket. Be careful not to bend
display pins when inserting display in socket.
d. Reinstall display bezel.
3-14. Replacement of Probe Controller Fuse
(52, fig. FO-8).
a. Unscrew fuseholder cap and remove fuse.
b. Insert new fuse in cap.
c. Reinstall cap in fuseholder.
3-4
