Advertisement
i
O'
0
Instrument oper
-
ating but
meter
indicator action is
uns
t
able or erratic.
" '
t!
416A004-l
10/26/55
Serial 79
and
above
Insufficient
voltage
at
inputs
o
L
Check RF
POWER
MONITOR 0
a
0
Tuning eye aperture should
be open
not more than approximately
1/4
11
0
If aperture is wider
than
1/4
11
:
( 1)
Check that levels of
incident
and
reflected
voltage inputs
are with
-
in
rated
limi
ts
0
(2) Check
adjustment
of tuning eye
circuit
(see Adjustments)
:
(3)
Localize
trouble
in input
cir-
cuit (see steps 2 to 7)
0
b
0
If
tuning eye aperture
is approxi-
mately 1/4
11
or
smaller, localize
trouble
i
n
circuit subsequent to
filters (steps 8
and
9)o
2
0
To localize trouble between the
power
supply and instrument
circuit,
dis
-
connect the 75
- volt,
210-volt, and
250-volt supplies from the instru
-
ment circuit, terminate each with an
appropriate
dummy load
to ground,
and
check the power supply, as
de
-
tailed
below
o
NOTE
:
Disconnect
power cable or
turn power switch to off
position before changing any
connections.
a
.
75-volt supply
:
unsolder the
two jum
-
pers from
pin
5 of V21, and connect
pin 5
of V21 to ground through a
22,
000 -ohm
1-watt resistor
0
b
.
210-volt
supply:
unsolder Rl2
l
from
capacitor
C66
,
and connect
Rl21
in
series with a
15, 000
-
ohm 5-watt
resistor to ground.
(Rl21
and
C66
are identified in Fig. 21.)
c
0
250
-
volt supply: at
p
in
3
of
Vl9
,
clip
jumper outgoing to capacitor
C60
(Fig. 21).
Connect p
i
n
3 of Vl9
to
ground through a 5,
000
-
ohm
20~watt
resistor
o
(
1)
If
input
voltages
are too low, in-
crease
le
vel at
external source.
(2) Readjust tuning
eye circuit, if
necessaryo
Advertisement
