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O"
I-'
I
Symptoms
Instrument op er
-
atingbut meter
indicator
action
is
unstable
or
erratic
(cont'
d)
.
Possible Cause
Insufficient
voltage
at
inputs (cont
1
d)
.
Trouble
in
power
supply
.
Trouble on 210
-
v
olt bus
.
Trouble on 250-
volt
or 7 5
-
volt
bus
.
Trouble in instru
-
ment.
Test
Procedure
2.
c
.
(cont
'
d)
NOTE
:
When reconnecting the C60
jumper
,
it may be soldered to
pin 2 (instead of pin 3) of Vl9.
d. Check the power supply output level
and
line regulation as described under
Adjustments
.
(
1) If rated output and/or regulation
are
not obtained
,
trouble probably
is in
the power
supply circuit.
Check
as
described abo
v
e under
"HV regulator
not
functioning"
.
(2
)
If
rated output and regulation
are
obtained trouble is in
instrument
circuits
.
Suggested localization
procedures are
given in steps
3 to
8
,
It is
recommended that local
-
ization
be performed in the order
given in
this chart
.
3
.
Reconnect the 210-volt supply (connect
Rl2
l to
capacitor C66 [erminal to
which is
connected jumper outgoing to
Rl8
and
RB2]
).
Again check power supply
output level
and
line regulation.
a
.
If
250
-
volt
output
and
regulation are not
obtained
,
turn off the power
switch,
and
check the 210-volt bus
with
an ohm-
meter for a possible short to
ground.
b. If output and regulation are obtained:
4
.
Disconnect the 210
-
volt
supply
,
and re-
connect the 75-volt and 250-volt sup-
plies
.
Again check power supply out-
put level and line regulation
.
If 250-
volt
output
and
regulation
are
not ob
-
tained
,
turn off the power switch
,
and
check the 2 50
-volt
bus and the 7 5
-volt
bus
,
with an
ohmmeter for
a possible
short to
ground
.
5
.
Set up
test procedure as
described un
-
der Adjustments and shown
i
n
Fig.
18
,
and measure voltage levels at input to
aAoqB
pm:.? 6l Bn.ras SS/9.'Z/OI
I
-;-
f700V9If7
Remedies
a.
Loc
ate and cle
a
r
short.
a. Locate
and
c
lea.r
short.
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