Tektronix 570, Manual

Page: 44 / 134

9 . 1% resistors making up the values of 49Sk-
1 w , 197k- l w , 100k- l w , SOk - l w , 20k- l w , 1 0k - l w ,
S k - 2w , 2k-Sw and lk-Sw.
1 0 . Ohmmeter with 0 - l k , 0 - lOk and 0 - 1 00k
scales.
Preliminary
P reset the front-panel controls of the Type 570
as follows:
FOCUS
counterclockwise
INTENSITY
counterclockwise
ASTIGMATISM
counterclockwise
RANGE DC VOLTS 140
INDICATION
+ DC
STEPS/F AMILY
midrange
STEPS/SEC 1 20 counterclock-
wise
ST AR T ADJUST
midrange
VOLTS/STEP
1
PLA TE-SCREEN- P L ATE
GRID
MA/DIV 1
PLATE-GRID PLATE
VOLTS/DIV
1
POSITIONING
midrange
( V E RTICAL and
HORIZONT AL)
P E AK VOLTS
100
SERIES LOAD
10k
HEATER
6 . 3
HEA TER VARIABLE counterclockwise
+ DC 100
+ DC VARIABLE clockwise
-DC counterclockwise
POWER- MAIN OFF
POWE R-TEST ON
TEST POS ITION
OFF
Before applying power t o the instrument the
r esistances of the power supplies should be
c hecked. The typical resistances of the supplies
m ay be found in the chart below.
Also check the - 1 50 27k test panel connector
for 27k between the test panel connector and the
- 1 50 volt supply.
Connect the power cord and the ac voltmeter
to the output of the autotransformer. Turn the
P O W E R - MAIN to the ON position and adjust
the autotransformer for an output of 1 17 volts
( o r 234 volt s ) . Allow the instrument to warm
up for several minutes
before proceeding
w ith the calibration adjustments. During cal­
ibration, periodically check the input voltage to
the instrument and adjust t h e autotransformer
as necess ary to maintain the voltage at 1 17
o r 234 volts except when the power supply
r egulation is being checked.
NOMINAL RESISTANCES OF
POWER SUPPLIES
P O W E R
APP ROX RES ffiTANCE
SUPPLY
TO G ROUND
- l S0v
10k
+ 100v
20k
+ 300v
30k
+ 400v
30k
F LOATING
P O W E R
SUPPLY
+ 400v
lOOk or higher
-300v
lOOk or higher
CAUTION
Do not reset the - 1 50 ADJ Control
unless you are planning to perform
a complete calibration of the instru­
m ent.
1.
low-Voltage Power Supplies
Connect the de voltmeter between the + DC
connector on the test panel and ground. Set
the - 1 50 ADJ for exactly a reading of + 100
volts on the voltmeter. Now connect the
voltmeter to the - 1 50 volt test point. If the
- 1 50 volt reading is not within Zfo of - 1 50
then RS36 must be paralleled by RS37 , a
s elected value.
RS37 is selected so that when the - 1 50 ADJ
is set for exactly a reading of + 100 volts ,
the 150 volt supply will be within 2% of being
- 1 50 volts.
Check to see that the + 100 and + 300 volt
regulated power supplies are within 2% of the
proper voltage.
Under no condition is the
- 1 50 ADJ to be reset after the adjustment
des cribed above.
5 - 2
C alibration Procedure - Type 570
A A