AT&T Leich MAGNETO Instruction Manual

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Copyright, 1945, by
American Telephone and Telegraph Company
Printed in U. S. A.
BELL SYSTEM PRACTICES
Station Installation and Maintenance SECTION C41.106 Iuue 1, 9-30-45
AT&T Co Provisional
MAGNETO STATIONS
LEICH SET
1. GENERAL
1.01 This section gives general information relating to the
apparatus, use, connections and maintenance of Leich
magneto station wall sets.
1.02 Hand sets furnished with these wall sets are not of the
Leich types and maintenance information for the hand
sets is covered in other sections.
Z, APPARATUS AND USE
2.01 The Leich sets are wood wall sets having a dark oak
finish. The sets are of the anti-sidetone type and are
equipped with biased high impedance ringers. Sets may be
obtained with either a three or five bar hand generator, as
desired.
2.02 Code and piece part numbers of apparatus or parts
which may be required for replacement purposes are
listed below.
Leich Code or Pi-
Part No.
533A-2600
535A-2600
3A Generator
SA Generator
3C Hookswitch
26 Induction Coil
SA-2600Ringer
Pc 1086
Pc 1087
Pc 1092
Pc 1093
Pc 1098
Pc 1161
Pc 1164
Pc 1166
Pc 1185
Pc 1207
C41.106
Pace1
Description of Apparatus or Parts
Oak wall set having 3 bar hand generator
Oak wall set having 5 bar hand generator
3 bar hand generator
5 bar hand generator
Switchhook and switchhook contact as-
sembly
Anti-sidetone coil used with 335A-2600 or
535A-2600 Magneto Telephones
Biased high impedance ringer equipped
with gongs and gong standards
Gong locknut
Hexagonal nut for gong
Adjusting pivot for ringer
Locknut used with Pc 1092
Ringer magnet
Ringer biasing spring
Spring bracket for Pc 1161
Ringer armature
Generator magnet
Generator pinion
MAGNETOSTATIONS
LEICHSET

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Page 2
Leich Code or Piece
Part No. Description of Apparatus or Parts
Pc 1208 Generator pinion spring
Pc 1211 Generator gear
Pc 1214 Hub collar for Pc 1211
Pc 1215 Cap for Pc 1207
Pc 1240 3 bar generator armature
Pc 1241 3 bar generator gear shaft
Pc 1242 Generator contact assembly
Pc 1245 Generator crank and handle
Pc 1268 5 bar generator gear shaft
Pc 1270 5 bar generator armature
Pc 1546 Ringer yoke
Pc 2961 Locknut used with ringer yoke
Note: If screw of screw terminals requires replacement
the standard P-136632 screw (1/4" 6-32 galv. B.H.M.
screw) may be used.
3. INSTALLATION
3.01 Attach Leich sets to the various mounting surfaces with
the fasteners regularly used for attaching subscriber
acts.
3.02 The generator crank and handle and the hookswitch
lever (switchhook) are enclosed in a small envelope
placed inside the set. Attach hookswitch lever to the contact
assembly as indicated in Fig. 1. Place generator crank and
handle on generator in the usual man~~ru.' , ./
I I I'
l ! ! -.......
' I '
I I I
1, ' I I'
LoosenS'Nitchhooksetscrew,press
against upper end of hing::d O;Jeratlng
arm and slide switchhook through
slotted hole in side of set and
under set screw as shown.
Tighten set screw. Fig. I

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3.03 Where the use of a condenser in the induction coil
network is required (see 4.01) mount an 1149B 1/2 mf.
condenser on the door of the set as indicated in Fig. 2 (1st
position). Attach condenser with strap P-225255 and two 1•
No. 6 R.H. blued wood screws. Where it is local practice to
connect a condenser in series with the talking circuit, mount
a 149A 1 mf. condenser in the same location. If a condenser
is also required for the induction coil network, mount it in loca-
tion shown as 2nd position in Fig. 2.
FirstPosition
r----------------------------1;
2¼ in. : SecondPosition :F"" r~'-"2M· 'c'...Y
,--1.----------------- ------ 1..1...,,
1JinL~[ ______________________}~;
Fig.2
3.04 Where a KS-8058 (400 ohm) resistance is to be used in
the induction coil network, attach it directly to ter-
minals designated A and R in Fig. 2.
4. CONNECTIONS
Induction Coil Networks
4.01 The induction coil in the Leich set is equivalent in
electrical characteristics to the 104A induction coil used
in other magneto station sets. To obtain satisfactory sidetone
balance when used on the different types of subscriber loops
employed in the Plant, the induction coil networks used with
the 104A induction coil are also used with the Leich sets.
Table 1 in•licates the connections to be made in the sets to
obtain the proper network for the transmission codes specified
on the service order.
C41.106
Paael MAGNETOSTATIONS
LEICHSET

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TABLE 1
Zone Code Network Connection• (See Note)
MA
MB
MC
MD
Connect an •1149B (1/2 mf.) condenser be-
tween A and R
Connect a KS-8058 (
400 ohm) resistance be-
tween A and R
Connect an 1149B (1/2 mf.) condenser be-
tween C and R
Strap P-294521 or a piece of wire from C to R
•Condenser or resistance must be ordered sepa-
rately unless otherwise specified locally.
Note: Terminals A, C and R may not be designated in
the sets but location of these terminals is shown in
Fig. 2.
Line and Ringer Connection•
4.02 Line and ringer connections for the sets are the same
as those shown in Sections C64.141 and C64.142 for
high impedance ringers on magneto non-polarized ringing lines.
The short green ringer lead of the SA ringer corresponds to
the black ringer lead and the longer green ringer lead corre-
sponds to the red ringer lead of ringers in other station sets.
4.03 To facilitate making ringer connections three terminals
are provided on the door of the set just below the
ringer. These terminals are permanently connected to the Ll,
G and l2 terminals (line terminals) of the set but are not so
designated in the set. Lo.cation of the respective terminals is
shown in Fig. 3.
4.04 Where it is local practice to connect a condenser in
series with the talking circuit, connections to this con-
denser are made by cutting the loop provided in the green
wiring conductor which is turned back in the wiring form on
the door and then soldering the cut ends of the loop on the
lugs of the 149A condenser.

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0
Fig.3
Ringer Connection Limitations
- , - Green
!
t 8rown
1
White
2
4.05 Not more than 8 of the 535A sets (5 bar hand gen-
erator and
26(){)<d
ringer) should be connected to a
bridged ringing line having a loop resistance of lOO{)<d.The
number of sets which may be connected to lines of greater or
less resistance is in inverse proportion to the loop resistance,
e.g., 4 for a line with a
2000w
loop and 16 for a line with a
500"'
loop, etc. Where these limits are exceeded it will be nec-
essary to use other standard 5 bar hand generator sets such
as the 417P. In general, the 533A sets (3 bar hand generator
and
2600"'
ringer) are used on divided ringing lines but
if
used
on bridged ringing lines not more than 8 of these sets should
be connected to a line having a loop resistance of
800w.
The
permissible number of sets for bridged ringing lines of greater
or less resistance is proportional as in the case of the 5 bar
generator sets.
4.06 On bridged ringing lines the permissible number of
normal station ringers on the line shall be reduced by
one for each loud ringing bell connected thereto (392B or 592B
subscriber set).
C41.106
Page
5
MAGNETOSTATIONS
LEICH
SET

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t'aa-e6
Leich Set Connections
4.07 The connections for the Leich set are shown in Fig. 4.
On some of the sets the terminal designations shown
on the circuit label for the hand set cord may be incorrect but
the black, red and white conductors of the hand set cord should
be connected respectively to terminals 2, 3 and 4. These ter-
minals may be marked Y, R and G.
In
terminating hand set
cord, secure cord stay hook under screw head of terminal 1
(vacant). Some care is required in passing stay hook through
cord hole in side of set to avoid damaging hard rubber grommet.
Batt'"_-- -.,,R
Red
F"as.
4
5. NUMBER CARD HOLDER
Handset
Cord
5.01
If a station number card is required, either P-215591
or P-225816 may be attached to the front of the door
of this set as indicated in Fig. 5. The station number card
holder and station number card should then be added.

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ForP-225816
50JApparatusBlanklessClampingPlate
P-225815and ScrewP-136486
No.44 (.086) Drill 3/a /,--1---- .•.
in. deep.Starting / I ', 21/
64 ,n.Drill approx.
holefor ½ in.. • / i /, ¼ in. deep.
No.6 F.H.W. ~1-~ ½z in.--i4- ./ ·\ Clearanceholefor
Screw. . .1 .....____ . H~. ;rugon apparatus
1--:·-----~,.;:_-:4)~--1¾
2 in.} blank.
. \ '$--L I
l \ j /
' i ,/
_____ J_ _,/.
2½ in.
l
ForP-215591
50HApparatusBlanklessClampingPlate
P-215576and ScrewP-210167
No.44 (.086) Drill 3/
8 _,---r·-.,,
in.deep.Starting ,' 1
~·
\o/s,n. ',, 1/sin. Drill approx.
holefor ½ in. / 1 1--! -! , ¼in. deep.
No.6 F.H.W. ( ½s '"·Tp
~ \Clearanceholefor
Screw. 1 \ lugon apparatus
Ti___ - Jblank.
\ I
I I I
I \ /
2•12in. ',, I ,/
I --r---
. <t
Fig.S
I. MAINTENANCE
Hand Generator
6.01 The automatic cut-out should positively open and close
contacts when the handle is rocked back and forth to
the point where the armature just starts to turn. If the cut-out
fails to operate properly, correct this condition when possible
by adjustment of the contact springs or lubrication of the mov-
ing parts with a small amount of oil per KS-6232. The oil may be
applied with a toothpick. If the contact springs require adjust-
C41.106
Pqe7
■ AGNETO STATIONS
LEICHSET

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ment adjust these as necessary with a No. 466A tool or equiva-
lent without making a visible kink in the springs. Follow be-
tween front and transfer springs should be approximately 3/64...
Gauge by eye. See that the tension on the transfer spring
is
sufficient to assure that the back contact will be made in the
normal position.
6.02 When operating the hand generator
if
there
is a ten-
dency for the shaft to stick or turn hard due to lack
of
lubrication apply a slight amount of oil per KS-6232 with
a
toothpick at the oil holes provided in the shaft bearings. If
after lubrication the generator still turns hard, it may be due
to poor insulation of the bushings in the spring pile up or
partial short-circuit in the armature.
If
the generator turns
freely but no ringing current is applied to the line terminals,
spring adjustment may be faulty or
armature
winding open.
Switchhook
6.03 When the hand set is removed from the hook, the
switchhook shall move upward freely without binding
and
come to a positive stop.
If
switchhook binds on the
hinge
pin,
replace entire switchhook assembly.
6.04 Contacts shall make with a perceptible follow. Separa-
tion between contact springs shall be minimum .010...
Gauge
by eye.
Ringer
6.05 Ringer gongs are eccentric and where gong adjust•
ment is necessary, loosen the hexagonal nut and locknut
and rotate gong as required. Retighten hexagonal nut and
locknut.
6.06 If armature sticks or binds on adjusting pivot remove
and clean pivot in the same manner as for other
ringers
with
adjustable pivots. Replace adjusting pivot.
6.07
As adjusted by the factory ringers will generally oper-
ate satisfactorily under most conditions encountered on
lines
to which the sets are to be connected. Some improvement
in ringing efficiency may be obtained in some cases by changing
the biasing spring tension.