Maintenance - Bell System Practices 851 Identification, Installation, Connections, And Maintenance

SECTION 503-601-1 01
make sure assembly snaps into place. If cap does
not snap in place properly, rotate 90 degrees.
4. CONNECTIONS
4.01
For sets equipped with a 66S1-type connecting
block, terminate IW cable as shown in Fig. 26
and 27 using the terminal identification information
inside the housing as a guide in locating terminal
numbers (Fig. 16).
Fig. 16-Connecting Block Terminal Information
4.02
All leads or straps involved in service or
option changes are equipped with spade
tips. If not factory terminated, leads are insulated
and stored.
4.03
For sets equipped with the KS-16671L1
connector, (Fig. 6) an A25B connector cable
is required.
4.04
Connection Index:
Table B- Connections for KTS and/or Station
Busy Lamp
Page 10
Table C-Pickup-Signal Key Conversions
Table D-Polarity Guard Connections for
2851-Type Telephone Set [819041971
(P-90Dl97) Guard Assembly)
Table E-2A1 Matrix Block Connections
Fig. 24-Exclusion Switch Connections
Fig. 25-Hold Lamp Connections
Fig. 26-851BT, 851B, or 851BM Telephone
Set, Connections
Fig. 27 -2851BT, 2851B, or 2851BM Telephone
Set, Connections
Fig. 28-851CM Telephone Set, Connections
Fig. 29-2851CM Telephone Set, Connections
5. MAINTENANCE
5.01
Maintenance replacement should be limited
to the following:
• Complete telephone sets
• Modular items
• Optional items
• Replaceable components.
5.02
When dial replacement is necessary in the
851-type telephone set, use an 8RA dial for
nonspeakerphone sets and an 8CA dial for sets with
speakerphone. Remove dial by loosening adapter
mounting screws and springing dial brackets
sufficiently to release dial from locating pins.
Tran~fer
adapter brackets from dial being replaced
to new dial (Fig. 12).
5.03
Maintenance of the 35-type TOUCH-TONE
dial is not recommended and the dial should
be replaced. Adapter brackets are not involved
when replacing the TOUCH-TONE dial.
5.04
When necessary to remove housing, the
faceplate must first be removed by using a
KS-21107 type releaser or equivalent in catch in
bottom of faceplate. Housing can then be removed