AT&T Bell System 1A Hardware Tests And Adjustments

BELL SYSTEM PRACTICES
Statioa la,tallatioa aad Maiateaaace
SECTION C64.204
h111e
~
Dec., 195'
AT&TCoStaaclard
CODE
CALLING SYSTEMS
lA AND 1B
TESTS AND ADJUSTMENTS
1. G£NERAL
1.01 This section covers the tests and adjustments to be
made on the apparatus associated with the IA and lB
Code Calling Systems including the signals which · are also
used in conjunction with the 2A and 2B Code Calling Sys-
tems covered in the P.B.X. Ins!allation and Maintenance
Practices.
l.02 This section is reissued to convert it tq letter size and to
incorporate material from the addendum in its proper
location. In the process of this convP.rsion, marginal arrows have
been omitted.
1.03 The commercial power supply should be discon-
nected from the apparatus before disconnecting the
signals or attempting any repairs. Disconnection of the
power supply will not usually bt· necessary when making tests
and adjustments.
1.0 4 If any operating or key
·
unit or apparatus part
be··
comes defective and cannot be adjusted by the
methods described in this section a new unit or part shaH
be installed and the defective unit or part shall be returned
for repair.
Z. CODE SENDING STATION
2.01 A method of disassembling and reassembling the
code sending station is shown in Fig. 1.
Take out these
screws
to,-,-f7".e::....rt-;,t,:;;; ,;:.:,:;,~
remove top.
To remove operating
unit take out
these four screws.
This alzo loosens
the base from
the key units
so that all may
be separated
as
here shown.--
Latch plate pin
which may be
removed after
removing operating
unit by pulling
upward .
perating Unit
Key Unit
Key Unit
Fi(I'. 1--40-Code Sendia1r Station
for IA Syatem
2.02 CJeaaina: Dust and metallic particles shall be re-
moved from the commutator of the operating unit by
wiping with KS-2423 Cloth. Do not use ordina:ry rags or
cheesecloth, as lint may get into the operating unit mech•
anism.
2.03
Lul,ricatloaa
On the List 1 units there are two bearings
at the end of the cam shaft opposite the motor, one
supporting the main cam shaft and the other the cam which
controls the motor circuit. List 2 units have, in addition, a
bearing at each end of the upper cam shaft. All bearings are
.equipped with oil-saturated felt washers. When lubrication
becomes necessary, these bearings should be lubricated with
KS-7470 oil applied to the felt washers or by touching the
washers with a piece of bare wire which has been dipped into
the oil The bearings of the List 1 units may be reached by
removing the back of the set. However, it will be necessary to
remove the List 2 unit from the case for lubrication by removing
the screws from the bottom of the case. The two bearings for
the upper cam shaft then may be reached from the top of the
unit. The bearing for the lower cam shaft and for the motor
control cam may be reached from the bottom of the unit. Oil
should be applied sparingly to the teeth of the gears connecting
the upper and lower cam shafts.
Note:
The motor
is
a sealed unit and needs no lubrication.
2.04
Armature SJ>l'Ul(I':
The retractile spring referred to
in Fig. 2 is
for
the purpose of pulling the armature
away from the pole face and ordinarily requires no adjust-
me12t
in the field,
Retractile
Spring
Comm~tor
To Increase or decrease-tension on retractile spring loosen
this screw and adjvst arm until proper tension is obtainei!
then tighten screw. The tension should be changed only
a smali
amount at
a
time.
"""l1>.V1"'"1a1...1.·oosen
nut
(P202816)
slightly
Air Gap
Busy Lamp (6 Watt. 130V., Candelabra Base)
Fig. 2-0peratiq Unit of Code Sendia,: Station
2.05 Speed: The code sending station should complete one
cycle (3 complete codes) for si~ 26 in approximately
30 saconds. Replace the code sender, 1f necessary, as there is
no
adjustment for speed of the synchronous motor.
2.06 B"CIIJ'
Lamps Note that the busy lamp flashes the
selected code
as
the signals sound. Replacement lamp,
~S-1/4
watt, 110 to 125
volt, candelabra base.
2.07
Ke,- Unlta require no adjustments or lubrication. Re-
place any units that become defective,
2.08
Cord■
and Plq•
shall be replaced if found badly
frayed or defective.
Copyright.
1956.
hy American Telephone and Telegraph Company
Printed
in L'. S . A .
Page 1