Bell System Practices 564HK Service

BELL SYSTEM PRACTICES
AT&TCo Standard
1. GENERAL
This section contains connection and maintenance
1.01
information on the 564HK (MD) and 564HL
telephone sets.
This section is reissued to include information
1.02
on A20B connector cable.
2. MAINTENANCE
The 564HK set with D30C cord may be
2.01
subject to poor key button illumination in
multiple station, long loop situations due to the
omission of lamp ground straps on the cord plug.
When investigating poor key button illumination
2.02
involving 564HK telephone sets:
(a) If the station termination is made on a
66E3-25 or 66E4-25 connecting b l o c k ,
loop-through straps can b e installed o n connecting
block clip terminals 5,
the necessary lamp ground copper for lamps 2,
3, 4, and 5.
brought to the connecting block from connecting
key system apparatus via inside wiring or A-type
connector cables.
(b) If station termination is made via •A20B•
connector cable, or at a 3-way bridging
adapter, or equivalent, it is impractical to
field-modify either the plug of the D30C telephone
set cord or its mating connector on the A-type
connector cable.
be replaced with a 564HL.
Remove and replace housing as follows:
2.03
(1) To remove housing, loosen captive screws
in base of set. Lift housing up and toward
front of set.
(2) To replace housing, guide lower front of
housing over pushbuttons, align housing with
base of set, and gently press housing into place.
Tighten captive screws in base of set.
Scanned by Frank Harrell, (Cowboy Frank) Castle Rock, Colorado
SSP 502-541-407-i03_1973-06-0L jpg
564HK AND 564HL TELEPHONE SETS
11, 17, 23, and 29 to add
In all cases, full pairs should be
Therefore, the 564HK should
© American Telephone and Telegraph Company,
SERVICE
Replace cracked pushbuttons or collars.
2.04
Remove accumulated dirt or film from lamps,
collars, and pushbuttons with a water dampened
cloth.
DO NOT USE SOL VENTS OF ANY
If cleaning does not correct binding of
KIND.
pushbuttons, replace button and collar assembly.
Maintenance of handsets, dials, and ringers
2.05
is outlined in sections covering these
components.
When replacing a defective lamp use a
2.06
KS-6320 orange stick to extract the lamp
from its socket, and install the new lamp with its
contact surfaces properly aligned with the lamp
socket.
Maintenance of the 636-type key consists of
2.07
It
cleaning contacts with a 265-type tool, and
checking for loose or broken connections.
No field m aintenance sho uld be
performed on the plug of plug-ended
mounting cords.
Replace set if the following requirements
2.08
cannot be met:
(a) When depressed locking plunger should, on
its downstroke, release any previously locked
plunger.
(b) When any pushbutton plunger is released
from its operated position, it should return
with a snap to its nonoperated position.
(c) An operated key plunger should not release
during downstroke of hold button.
(d) An operated key plunger should release from
its operated position on the upstoke of the
hold button.
Printed in U.S.A.
Feb 02,2012 19:08:56
SECTION 502-541-407
Issue 3, June 1973
1973
Page 1