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CALIBRATION
MODEL 244
f).
Turn the 244 OUTPUT switch
off.
Connect
the W-1
to the 244 output
and the dc output
on
the W-1
to the 662.
See the 662 controls
as
follows:
RANGE FULL SCALE
-50
volts
NULL FULL SCALE
-100 In"
DIALS
-10.000
POLARITY
(-)
g).
Turn the 244 OUTPUT switch
on and set Cal.
Pot.
R145 for
-10 volts
+lO m" reading
on 662.
Cut jumpers
BCP088 R140, R141 and R142 as neces-
sary
to set Cal.
Pot.
Turn
244
OUTPUT switch
off.
5.
Overload
Calibration
a).
Connect
Loading
Box LB-1 Fixture
to output
of 244 and set for
- and lk-3kV.
put for
-2000 Volts.
set Voltage
Out-
Turn
244 OUTPUT
8"ltch
on.
b).
Adjust
load until
244 overload
light
comes
0".
If meter
on test
fixture
now reads
11.0 mA
to 11.9 nA resistor
R124 is already
optimum value.
If
reading
is not within
this
range
replace
R124
with
one selected
from table
below.
Turn OUTPUT
switch
m
before
changing
resistors.
current
in "IA
R124 in OHMS
10.2 - 11.0
42.2
45.3
already
installed
48.7
12.9
- 13.9
52.3
13.9 - 15.0
56.2
c).
If
overload
current
is less
than 10.2 mA or
greater
than 15.0 mA change Q107 as IoL dependent
on ",,,o
of Q107.
Turn 244 OUTPUT switch
OFF.
6.
Short
Circuit
Output
Current.
a).
Set 610B on 30 mA range
(Multiplier
-30
Range 10d3 Amperes Meter
-) connect
to output
jack
on 244.
b).
Set all
controls
on 244 fully
CCW and turn
244 OOTPO'I
switch
on.
610B should
read 12.0 ,,,A
to 14.0 nA and over
load
light
should
come on. If
reading
is higher
change Q107.
Turn 244 OUTPUT
switch
OFF.
7.
Load Dependent
Oscillations.
a).
Connect
Decade Capacitor
Box to 244 output
through
MH" TEE Connector.
b).
Set oscilloscope
as follows:
TIME BASE
1
MSIDIV
TRIGGER
INTERNAL
VERTICAL SENSITIVITY
1 WIDIV
c).
Connect
oscilloscope
to 244 output
through
NH" TEE connector.
Set
244
for
-200 volts
and
t"rn
OUTPUT switch
on.
d).
Step
Decade Capacitor
Box from zero to 1.0
MF in 0.1 MF steps
while
observing
scope.
No
oscillations
should
occur.
Disregard
line
spikes
which may or may not appear.
e).
Turn output
switch
OFF.
8.
234
Volt
Operation.
a).
Turn
244
Foyer Off and unplug
from variac.
Set 117-234 volt
switch
on rear
of 244 to the 234
volt
position.
Set
244
controls
for
-200 volt
output.
Plug 244 into
234 volt
line
and turn
Power Switch
on.
b).
Set,ehe
661 controls
as follows:
RANGE FULL SCALE
NULL FULL SCALE
DIALS
POLARITY
c).
Connect
the 662 and
Fixture
W-1
to Output
of
Co""ectar.
Connect
Scope
w-1.
500
volts
10 volts
200.00
(-)
High Voltage
Divider
244 thrbugh
MH" TEE
to
ac out
conneCtor
on
d).
Set scope controls
as follows:
TIME BASE
1 MS/DIV
TRIGGER
INTERNAL
VERTICAL
SENSITIVITY
1 Mv/DIV
e).
Turn
244 output
on.
662
should
read -200
il
volt.
Set Short-Open
Switch
on W-1
to open.
Noise
observed
on scope should
be less
than 200
microvolts.
Set Short-Open
Switch
on w-1
to
Short.
f).
Turn 244 output
and power switches
off.
Unplug
244 from 234 volt
line.
Set 117-234 volt
switch
back to 117 position.
C.
Final
Calibration.
1.
Re-check
Zener Adjust
and Calibrate.
2.
Load @gulstion.
a).
Connect
Loading
Box LB-l
Fixture
to 244
output
through
MHV TEE Connector
and set
for
-
and lk-3kV.
Set
244
controls
for
-2000,volts.
b).
Connect
W-1
Divider
to 244 output
through
MVH TEE Connector
and connect
W-1
DC output
to
662.
20
0771
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