Tektronix 570, Manual

Page: 48 / 134

MA/DIV Accuracy Check
MA/DIV Resistor Deflecrion obtained from
Setting Value
BOHom Graticule Line
10 l k - 5 w 1 0 divisions
S
2k-Sw 1 0 divisions
2
5 k - 2 w
1 0 divisions
1 1 O k - l w 10 divisions
. 5 20k-lw 1 0 divisions
. 2
5 0 k - l w
1 0 divisions
. 1 100k-lw
10 divisions
.05 1 9 7 k - l w
1 0 divisions
.02 495k-lw 1 0 divisions
Remove all connectors.
1 0 . Adjusting VOL TS / D I V BAL (located 1 u n d e r
instrument)
Turn the PLATE-GRID Control to PLATE
and connect the P and K connectors on the test
panel together. Now rotate the VOL TS/DIV
C ontrol and at the s ame time adjust the VOL TS/­
D I V Control for no horizontal movement of the
spot on the crt. Disconnect the jumper between
the P and K connectors on the test panel.
1 1 .
Setting VOLTS/STEP Z E R O ADJ.
Turn the PLATE-GRID Control to GRID, the
VOLTS/DIV Control to
. 1
and the START
ADJUST Control full counterclockwise. With
a jumper ground pin 8 of V 1 1 5 . While pressing
the Z E RO B lAS button position the spot under
the center vertical graticule line with the
HORIZONTAL POSITIONING
Control. Release
the Z E RO B lAS button and return the spot
under the center vertical graticule line with the
VOLTS/STEP Z E RO ADJ Control. Disconnect
the jumper between ground and pin 8 of V I I S .
1 2 . Setting the Knob Position of the START
ADJUST (SN 5200-up)
Press the Z E RO B lAS but�on in and set the
s pot under a convenient reference line on the
graticule. Release the Z E RO BIAS button and
position the start of the dots under the same
reference line using the START ADJUST to do
the positioning.
The dot on the knob of the START ADJUST
s hould now be pointing at the
0
in the front
panel.
If your instrument is below serial number
5002 and you would like to know the start
pos ition then do the above procedure and mark
the zero on your front panel in pencil or ink.
1 3.
HOR GAIN Adjustment
Turn the PLATE-GRID Control to PLATE ,
the VOL TS/DIV Control to
10,
the MA/DIV
C ontrol to 50 and the S E RIES LOAD Control to
1
M. Adjust the + DC Controls for
100
volts
out of the + DC connector on the test panel
as explained earlier in this procedure.
Connect a jumper between the P connector
on the test panel and ground. Line up the spot
under the far left-hand graticule line. Now
connect the jumper between the P connector
and the + DC connector on the test panel.
Adjust the HOR GAIN Control until the spot
is under the far right-hand graticule line.
R e connect the jumper to ground and then to+ DC
s everal times to remove interaction. Remove
the jumper from the test panel.
1 4.
Setting VOLTS/STEP ADJ
Reset the PLATE-GRID Control to GRID,
the VOLTS/DIV Control to
.1
and the VOL TS/­
STEP Control to . 1 . Adjust the VOLTS/STEP
ADJ until there is one dot per graticule
division.
1 5.
Adjusting Volts/Div Cal (R227)
Reset the VOLTS/DIV Control
VOLTS/STEP Control to
10.
( s ee Fig 5 - 8 . ) for one dot
to 10 and the
Adjust R227
per gra ticule
division.
If
R227 does not have enough range of
adjustment , to set the crt display for one dot
p e r graticule division , then R228 may be
p aralleled by a selected resistor R226.
NOTE
S t eps 1 3 , 1 4 and 15 interact, there­
fore they should be repeated several
times.
After the interaction has been eliminated the
VOLTS/STEP and the VOLTS/DIV Controls
s hould be checked against each other for a
one dot per graticule division display when the
s witches are set the s ame value, i . e . , 5 and 5 .
1 6. M I N N O C U R V E S Adjustment, a n d
M a x i m u m N u m b e r o f Curves and S I N -
GLE FAMILY Button Check
Turn the STEPS/F AMIL Y Control full
co unterclockwise and adjust the MIN NO CUR VES
5
-
6
C alibration Procedure - Type 570