BELL SYSTEM PRACTICES
AT&TCo Standard
SECTION 573-127-703
Issue 5, May 1972
1.
2.
28E AND 28H TRANSMITTER DISTRIBUTOR UNIT
ADJUSTMENTS
CONTENTS
PAGE
GENERAL
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2
BASIC UNITS ...............
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4
Basic Gear Adjustments
Intermediate gear - transmitter
distributor gear backlash ........
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33
Clutch Mechanism
Armature bail spring . . . . . . . . . . . 28
Clutch latchlever spring . . . . . . . . .
6
Clutch magnet assembly
(preliminary )
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26-28
Clutch shoe lever .
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5
Clutch shoe lever spring . . . . . . . . .
4
Clutch shoe spring . . . . . . . . . . . . .
4
Clutch trip lever . . . . . . . . . . . . . .
6
Clutch trip lever spring . . . . . . . . .
6
Main bail latch spring . . . . . . . . . . . 28
Feed Wheel Mechanism
Feed pawl . . . . . . . . . . . . . . . . . . . 22
Feed pawl spring . . . . . . . . . . . . . . 22
Feed ratchet detent spring .
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Feed wheel detent. . . . . . . . . . . . . . 21
Main bail spring. . . . . . . . . . . . . . . 19
Main bail trip lever . . . . . . . . . . . . 19
Sensing pin spring
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Main Bail Mechanism
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Main bail
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20
Signal Contacts
Drive link spring
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25
Signal contact clearance .
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25
Signal contacts - electrical . . . . . .
29
Signal contact spring. . . . . . . . . . . .
25
Start-Stop Switch Assembly and
Tight-Tape Mechanism
Start-stop switch bracket. . . . . . . . .
16
Start-stop switch bracket (for units
equipped with tape lid sensing lever) .
17
Tight-tape intermediate arm . . . . . .
18
Tight-tape intermediate arm
spring . . . . . . . . . . . . . . . . . . . . . 18
Tight-tape start-stop contact
spring
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CONTENTS
PAGE
Tape Lid
Start-stop detent bail spring ...... .
Tape guide ................. .
Tape guideplate
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Tape lid ...................
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Tape lid release plunger spring ...
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Tape lid spring ..............
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Tape-Out Switch Assembly
9
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10
7
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9
Depressor bail torsion spring.
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Intermediate tape-out bail spring
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Tape-out contact assembly. .
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Tape-out contact bracket . . . . . . . . . 13
Tape-out sensing pin.
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Tape-out sensing pin (for units
equipped with tape lid sensing lever) . . 15
Tape-out sensing pin spring
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Top and Cover Plates
Cover plate
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Cover plate detent spring. . . . . . . . . 12
Top plate . . . . . . . . . . . . . . . . . . . 11
Transfer Mechanism
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Locking bail spring .
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23
Stabilizer spring . . . . . . . . . . . . . . 24
Transfer bail stabilizer
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24
Transfer lever spring.
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23
3. VARIABLE FEATURES. . . . . . . . . . 34
Auxiliary Contacts
Auxiliary contact operating
bail spring . . . . . . . . . . . . . . . . . . 43
Contact sensing arm . . . . . . . . . . . . 43
Contact swinger - operating
bail clearance . . . . . . . . . . . . . . . . 44
Normally closed contacts. . . . . . . . . 42
Normally open contacts . . . . . . . . . . 42
Code Reading Contacts
Contact assembly positioning . . . . . . 3 9
Contact sensing arm - upstop
clearance . . . . . . . . . . . . . . . . . . . 40
Contact swinger - sensing
arm clearance .
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