AT&T Bell System Plant Series Service Manual

BELL SYSTEM PRACTICES
Plant Series
SECTION 502-541-406
Issue 1, April 1970
AT&TCo Standard
SERVICE
564HD TELEPHONE SET
1. GENERAL
1.01
This section contains maintenance and
connection information on the 564HD (MD)
telephone set.
1.02
The information in this section was formerly
contained in Section 502-525-404 which is
hereby canceled.
2. MAINTENANCE
2.01
Maintenance of handsets, dials, and ringers
is outlined in sections covering these
components.
2.02
Removing and replacing telephone set housing:
(a) To remove housing, loosen captive screws
in base of set. Lift housing up and toward
front of set.
(b) 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.
2.03
The 564HD (MD) telephone set is equipped
with a D30B mounting cord which is rated
MD. When replacement of the mounting cord is
necessary, a D34B cord should be used.
ilt
No field maintenance should be
performed on the plug of plug-ended
mounting cords.
2.04
Early production 589-type keys were equipped
with vibration damper sleeves on contact
springs. Key maintenance should include checking
for loose or missing damper sleeves. Later
production keys of this type do not require this
vibration damper and are not equipped with damper
sleeves.
2.05
Replace cracked pushbuttons or collars.
Remove accumulated dirt or film from lamps,
collars, and pushbuttons with a water dampened
cloth. DO NOT USE SOL VENTS OF ANY
KIND. If cleaning does not correct binding of
pushbuttons, replace button and collar assembly.
2.06
Maintenance of the 589-type key consists of
cleaning contacts with a 265-type tool,
checking damper sleeves (2.04), and checking for
loose or broken electrical connections.
2.07
When replacing a defective lamp use a
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.
2.08
Replace set if the following requirements
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 upstroke of the
hold button.
3. CONNECTIONS
3.01
The 564HD (MD) telphone sets are factory-wired
for use with lAl, 1A2, or 6A key telephone
system (KTS). These sets can be modified for use
with lA KTS (Fig. 3) but are not intended for
exclusion or speakerphone use.
3.02
Telephone sets wired with the black and
red ringer leads on the RT and RR terminals
(c) American Telephone and Telegraph Company, 1970
Printed in U.S.A.
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