MOUNTING BRACKET
3
- +
AND
CLEAR R1 OR PLS FAULT — DISCIPLINED RUBIDIUM OSCILLATOR
PLS
S/N16
PHM
PIN 1
PIN 2
PIN 3
[9] Replace
R1
S/N44
S/N15
R42
90.9
measure resistance
between pin 3 of
No
Yes
[7] Using ohmmeter,
[4] Is
clock chain
cover removed
[8] Is
resistance
No
terminal of coil
and positive (
+
)
PLS
between 38 ohms
and 40 ohms
SCREWS (4)
FLATHEAD SCREW (4)
flathead screws and network
clock chain control cover
[6] At front of frame, remove four
panhead screws holding rear of
network clock chain control
[5] At rear of frame, remove six
R1
39.2
S/N17
[2] At appropriate power switch, ensure
power from clock chain (
OFF NORM
and
AND
OSC
OS
PLS
MSO
SCREWS (6 PANHEAD)
(FRONT)
CONTROL COVER
(REAR)
[1] See CAUTION 1. Obtain
volt/ohmmeter (KS-14510)
[3] Depress
ROS/OFF
switch to remove
ROS/OFF
switch is rotated
lamps lighted)
to
ROS
(
OS
and
OFF NORM
PWR OFF
lamps lighted)
Yes
Always remove
NCSU from service
and disable all
oscillators (using
switch) before
working on any
network clock
problem
ENABLE/DISABLE
CAUTION 1
Figure 3 — R1/PLS Circuit Schematic
Figure 2 — PLS Circuit (Front View)
[Figure 3]
switch [Figure 2]
Figure 1 - Network Clock Control
cover [Figure 1]
PAGE 1 of 2
234-151-013
Issue 8
TAP
DEC 1995
151
