TM 55-4920-401-13&P
CHAPTER 4
AVIATION INTERMEDIATE MAINTENANCE INSTRUCTIONS
Section I.
PREPARATION FOR MAINTENANCE, STORAGE, AND
RESHIPMENT
4-1. Preparation for Maintenance. There are no
special unpacking procedures. Unlatch and remove
the instrument case from the accessory case. Open
the accessory case, remove the dessicant, and check
for the items in table 3-1. Loosen the wing nuts on
the handle and rotate it to a comfortable position
for pushing. Retighten the wing nuts. The testeris
ready to be operated after unpacking.
4-2. Preparation for Storage. Place 5 eight-unit
bags of dessicant (item 1, table 1-16) in the
accessory case. Store the tester in a dry area where
the temperature range does not exceed -65 to 160°F
(-54 to 71ºC).
4-3. Preparation for Reshipment. Place 5 eight-
unit bags of dessicant (item 1, table 1-16) in the
accessory case. Surround the tester with 2 inches of
rubberized hog hair when packing for reshipment.
Use the latest revision of specification MIL-P-116,
method IIb, and JAN-P-100. A pallet (fig. 3-1) may
be prepared to secure the tester in the shipping
carton. Four holes in the pallet are for tie-down
straps.
4-3.1. General Information for Storage and Ship-
m e n t . F o r g e n e r a l t e c h n i c a l i n f o r m a t i o n on
preparation for storage and shipment, refer to
TM 55-1500-204-25/1. For regulatory requirement
pertaining to equipment placed in administrative
storage, refer to AR 750-1.
Section II.
CHECKOUT AND ANALYSIS
4-4. General. This section contains information
for testing the performance and accuracy of the
t e s t e r . T h i s i n f o r m a t i o n , t o g e t h e r w i t h
troubleshooting information contained in tables 4-4
through 4-11 enable maintenance personnel to
rapidly localize tester malfunctions.
4-5. Warmup Procedure.
a. Turn FUNCTION SELECT, STD DAY, and
MASTER POWER switches to OFF position.
b. Connect BH499A power cable to POWER
INPUT receptacle and to 115 vat, 50-400 Hz power
source.
c. Connect BH15184A power interconnect cable
to two INTERCONNECT connectors on testerdeck.
d. Place the MASTER POWER switch in ON
position and allow 15 minute warmup. POWER ON
lamp glows when power is applied to tester.
4-6. Checkout Instructions.
a. Temperature Indicator Accuracy Check.
(1) Make the test setup of figure 4-1.
(2) Place T/C INPUT switch in CHECK
(3) Turn FUNCTION SELECT switch to
TRIM.
(4) Turn TEMPERATURE switch to CAL
6 0 0 º C a n d a d j u s t C A L A D J p o t u n t i l t he
temperature indicator reads 600° C.
(5) T u r n T E M P E R A T U R E s w i t c h t o
OPERATE.
(6) Using temperature vs emf values in table
4-1 or other values equivalent to those in NBS
Circular 561 for a chromelalumel thermocouple,
check the accuracy of the temperature indicator
throughout its range (0° to 1399° C).
(7) The displayed temperatures shall agree
with the test signals + 2° C.
b. % RPM Indicator Accuracy Check.
(1) Turn RPM switch to CAL 100% RPM and
adjust rpm CAL ADJ potentiometer until display
reads 100.0% rpm.
(2) Turn RPM switch to N1 and short pin A to
pin B in RPM INPUT INSTRUMENT CABLE
receptacle. Display shall read 000.0 + 0.1% rpm.
(3) Turn RPM switch to N2 anad short pin C
to pin B in RPM INPUT INSTRUMENT CABLE
receptacle. Display shall read 000.0 + 0.1% rpm.
CABLE position.
Change 3 4-1
