61. Bitumeter Does Not Register or Operates Erratically
Probable cause
Possible remedy
Fifth wheel does not fully lower.
Inspect to determine if lift rod is bound.
Broken drive cable
Report to organizational maintenance.
Drive cable improperly lubricated
Lubricate the cable (para. 46)
Defective fifth wheel assembly.
Report to organizational maintenance.
Section IV. RADIO INTERFERENCE SUPPRESSION
62. Definition
a. Interference. The term (interference) as used here, applies to electrical disturbances in the radio
frequency range which are generated by the water distributor and which may interfere with the proper
operation on radio receivers or other electronic equipment.
b. Interference Suppression. The term (interference suppression), as used here, applies to the methods
used to eliminate or effectively reduce radio interference generated by the water distributor.
63. Purpose of Interference Suppression
The technical importance of effective interference suppression cannot be stressed too greatly. Since the
electrical disturbances generated by the water distributor are composed partly by electrical waves in the radio
frequency range, they must be suppressed for two important reasons: First, they will interfere with the proper
operation of both civilian and military radio sets, and second, they will enable an enemy to locate the
equipment and associated units.
64. General Sources of Interference
General radio interference is generated anywhere a spark occurs, or where a high frequency current is present.
A spark is a small amount of current jumping an air gap to response to the force to the relatively high voltage.
The gasoline engine ignition system is a common source. Magneto breaker points, generator commutators,
relay contacts, and static charges collecting on the frame are other common sources which in some way must
be suppressed.
65. General Methods Used to Obtain Proper Suppression
Essentially, suppression is obtained by providing a low resistance to ground for the stray currents. The methods
used to attain suppression includes: shielding the ignition and high frequency wires, grounding the frame with
bounding straps, and using capacitors and resistors where necessary.
66. Replacement of Suppression Components
a. General. Replacement of suppression components must be performed with parts identical to the
component being removed. All shielding capacitors must be exactly the same size and have the same
microfarad and voltage rating as specified in the original components.
b. Components. The suppression components include the following: magneto, spark plug cables, spark
plugs, ground straps, and associated hardware.
c. Replacement of Magneto Capacitor.
(1) Remove screw (8, fig. 18) and disconnect magneto stop switch wire (1 ) and high temperature
8
safety switch wire.
(2) Remove two screws (8) securing capacitor (9). Remove capacitor and 0-ring (10).
(3) Position new capacitor and O-ring in magneto and secure with two screws (8).
AGO 6871A
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