Tektronix 570 Manual Download Page 47

Page: 47 / 134

the  crt  base  clamp  and rotate  the  tube  with  the
alignment  ring.  When  the  trace  and the grat
icule  line  are  in  coincidence ,  push  the  tube

forward so that it rests snugly against the

graticule.

Then tighten the crt base clamp.

Recheck the alignment after tightening the

clamp to be sure it didnit move while the

clamp was being tightened.

CRT adjustment SN 5200-up

Loosen the clamp at the base of the crt

and push the crt against the graticule , then
tighten the clamp.

Now with the red knob ,

near the bottom of the clamp, rotate the crt

until the trace runs parallel to the horizontal
lines of the graticule.

Adjusting PHASE A a n d B a n d setting CRT

GEOM ADJ Control

G E O M

ADJ

Control for minimum curvature of

the vertical lines at the sides of the crt.

Disconnect the jumpers.

8. Checking Vertical Tube Balance

When the VERTICAL POSITIONING Control

is  in  its  midrange  position  the  dots  should
be  between  the  second  and  fourth division  line
as  measured from the bottom full graticule  line.
If  the  dots  do  not  lie  in  this  area then V280
and  V281  should  be  changed  until  the  near
b alanced  condition  is obtained.

VERT GAIN Adjustment and Checking M A / D I V

Switch

Turn the PLA TE-SCREEN-G RID Control to

SC REEN , the RANGE DC VOLTS Control to

1 4 0 and the INDICATION Control to + DC .

O n instruments below serial number 5 1 22 turn

the MA/DIV Control to .02 while on instru

ments above serial number 5 1 21 the control
is set to . 1 .

While observing the meter, set the + DC

Controls for exactly 140 volts , then switch the

INDIC ATION Control to HTR. Now position the

dots to the bottom full graticule line. Switch

the INDICATION Control to + DC and adjust the
V E RT GAIN Control for a deflection of 1 0

divisions.

Switch back and forth between the + DC and

H T R positions of the INDICATION Control to

remove interaction in the adjustment. B e sure

Fig. 5-4.

The waveform obtained in the

240

position

the STEPsl

that the dots are on the bottom graticule line

S E C Control, which i s used t o adjust the C R T GEOM

ADJ

Control.

each time you switch after setting the +

Set the PLATE-GRID Control to GRID, the

VOL TS/DIV Control to 1 and connect a jumper

from the P connector on the test panel to

ground.

Adjust the STEPS/FAMILY Control

for 10 vertical lines.

Adjust the PHASE A

Control for the flatest bottom on the wave
form.

Now turn the STEPS/SEC Control to

the 1 20 clockwise position and adjust the PHASE

B Control for the flatest top on the waveform.
Turn the STEPS/SEC Control to' the 240 position

and check for alternate switching, see figure

5 - 4.

Using the display obtained i n the 240 position

of the STEPS/SEC Control, adjust the CRT

position.

To check the ±3% accuracy of the MA/DIV

Contro I, set the+ DC Controls to obtain 100 volts.
B e sure to set the INDICATION Control to the

HTR position after setting the + DC voltage.

Turn the MA/DIV Control to 50 and position

the  dots  to  the  bottom  full  graticule  line.
Connect  the  lk-5w  resistor  between  the  + DC
connector and ground.  The dots will have moved
up  two  divisions .  Switch  the  MA/DIV  switch
to  20  and  check  to  see  that  the  dots  are  5
di visions  from  the  originally  set  point  (the
V ER TICAL  POSITIONING  Control  is  not reset
after  it  is  set  as  above).  See  the  table below

for the other settings of the MA/DIV Control.

C alibration Procedure - Type 570

5 - 5