SECTION I
GENERAL
support maintenance personnel to test and troubleshoot
1. Purpose and Scope. a. This bulletin contains
the AN'FRT-76 and -77 and its components down to the
calibration instructions for Oscillator/Modulator Test Set,
card level. Each major component of the AN/FRT-76
Litcom Model No. 4401 (oscillator/modulator test set),
and -77 is activated by stimuli from the
and is used by maintenance calibration personnel.
oscillator/modulator test set which simulates actual
Since maintenance calibration personnel are trained and
operating conditions. The oscillator/modulator test set
qualified in the use of test and measuring equipment,
contains circuits which perform frequency mode
detailed instruction concerning the operation and use of
selection, status display, audio monitoring (VU meter),
these equipments are not contained in this bulletin.
attenuation, and remote control functions in the
AN/FRT-76 and -77. The oscillator/ modulator test set
b. Integrated within this bulletin is an illustration
overall assembly is housed in an aluminum transit case.
which shows front panel controls and indicators.
The transit case consists of a base and detachable
cover. The cover contains a removable plate which
2. Reporting of Technical Bulletin Improvements.
stores the accessory items supplied with the
Reporting of errors, omissions, and recommendations
oscillator/modulator test set such as cables. The plate is
for improving this publication by the individual user is
secured to the cover by four fasteners. All operating
encouraged. Reports should be submitted on DA Form
controls of the oscillator,/' modulator test set are
2028 (Recommend Changes to Publications) and
mounted on the front panel assembly. Two handles are
forwarded direct to Commanding General, US Army
provided on the front panel assembly for convenience in
Electronics Command, ATTN: AMSEL-MA-CFA, Fort
removal of the oscillator/modulator test set overall
Monmouth, NJ 07703.
assembly from the transit case for servicing. The front
panel controls and indicators of the oscillator/modulator
3. Description. The oscillator/modulator test set is a
test set are illustrated in figure 1. Additional data is
portable equipment that provides maintenance support
listed in a, b, and c below.
for Transmitting Set, Radio AN/FRT-76 and -77. The
oscillator/modulator test set enables direct
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