Bell 300 Series Maintenance Manual

BELLSYSTEMPRACTICES SECTIONC38.549
StationOperationsManual Issue3, March,1960
StationSets AT&TCo Standard
TELEPHONE SETS- 300 SERIES
MAINTENANCE
1.00 INTRODUCTION
head of each. If absent, install Shakeproof
No. 3099-08-01 (C) lock washer or replace
1.01 This section covers the requirements and baseplate mounting screwwith special head
adjusting procedures for the maintenance RHM screw, P-467742.
of telephone sets of types 302, 304, 306, 307, 309,
332, 334, 354, 356, and 357. • Replace defective parts when parts are
available; otherwise, replace set. The 426A
1.02 The 300-type sets for specific uses are cov- electron tubes can be used to replace the
ered in other C sections. 313A, 333A, 372A, and 405 electron tubes.
2.00 GENERAL • When a 101A gong attachment is to be
used on a set equipped with a ringer volume
2.01 Inspect exterior and interior of telephone control, the gongs shall be interchanged
set for loose, displaced, or broken parts and and the gong attachment placed on the stao
determine if any such defects are responsible for tionary gong.
the trouble condition, prior to proceeding with
routine maintenance. 2.02 Table A lists some of the troubles that may
• Check baseplate mounting screw to make occur, their probable causes, and correco
certain there is a lock washer under the tive measures.
TABLEA
Trouble ProbableCauses Corrective Measures
Ringer disconnected or wired Connect correctly.
wrong in set
Open winding Replace ringer.
Metal particles in armature gap Remove particles with Scotch tape or ap-
Bell does not ring. proved equivalent.
No ground (party lines) Check ground circuit.
Open tube Short-circuit yellow and black tube lead.s
and, if ringer operates when ringing vol_-
age of correct polarity is applied, replace
tube.
Bell is too loud. Stroke limiting arm not prop- Reduce armature travel.
erly adjusted
Set on sound absorbent material Place set on hard surface or adjust stroke
Bell is not loud
or stroke limiting arm not prop- limiting arm.
enough, erly adjusted
© AmericanTelephone andTelegraphCompany,1960
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