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i
O'
.;::..
i
Instrument op er
-
ating
but meter
indi
c
ator
action is
unstable or erratic
(cont'd),
416A004 =1 10/26/55 Seriat 79
an'
d
above
Defective
filter
(cont
'
d)
o
Trouble
in
one of
the delayed A
VC
circuits or
one
of
the
multiar com
-
parator
circuits
o
Incident Channel
Reflected Channel
7
0
c
0
Filter 2
(
cont
1
d)
Signal side
of
C9
to
groundo
(Signal side
is
the back terminal on
the
edge of the filter
assembly which
is toward the rear
of the
instrument.)
CAUTION
:
Components of
the two filters
are
selected
and tested at the
factoryo
Under
no
circumstances
should
any
attempt
be made to
repa
i
r
filters
be
-
yond
locating
and resoldering
open
wiring
and connections
o
If
either
filter is
found
to
be defec
-
tive, a
matched pair should be ordered
;
see Table of Replaceable Parts
0
8
0
To
localize trouble in
a
delayed A
VC
or
multiar
comparator circuit
it is recom
-
mended that
the DC
voltages
for a tube
in a given circuit in
the
reflected
channel be compared
with
the DC volt-
ages
for
the tube
performing the car
-
responding function
in
the same cir-
cuit
in the incident channel
0
For ex-
ample, measure
the
DC
voltages at
tube VlO and compare them with the DC
voltages
measured at
VS
:
corresponding
voltages
for the two tubes should be
approximately the same, and within
±5%
of those shown
in
the schematic.
If
deviation
is
found, the trouble spot
probably
is in that section of the circuit
where the deviation occurs, and components
in that section of the circuit should
be
tested to find the
defecti
ve
parL
Replace any de-
fective component
Delayed AVC
Multiar
C omparator
V5,V6A,V6B,V7A
,
V8B
VlO
,
VllA
,
VllB, Vl2A, Vl3B
,
V8A
,
V7B
VI.3A,
V
l2
B
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