Tektronix 570 Manual Download Page 43

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SECTION 5

CALIBRATION PROCEDURE

The instrument should not require frequent

recalibration , but occasional adjustments will
b e necess ary when tubes and other components

are changed.

Also, a periodic calibration is

des irable from the standpoint of preventative

m aintenance.

Apparent troubles occuring in the instrument

are often actually

the result

of improper

c alibration  of one or more circuits. Consequently
this  section  of  the  manual  should  be  used  in
conjunction with  the  Maintenance  section during

troubleshooting work.

the instructions that follow, the steps are

arranged in the proper sequence for a complete

c alibration  of  the  instrument.  Each  numbered
step  contains  the  information  required to  make
one  adjustment  or  a  series  of  related  adjust
ments.

In each calibration step only the required

information is given.

Controls are assumed

to be set at the positions they were in during

the previous step unless specific instructions

are  given  to  change their  settings.  All  jumpers
are  disconnected  at  the end of each  step  unless
instructions  are  given  to  the  contrary.

It will be necessary for you to refer to the

c alibration steps immediately preceding the
adjustment you wish to make to determine the

proper settings for the controls not mentioned

in that step. Due to the interaction between
adjustments in the horizontal and vertical amp

lifiers , single adjustments in these circuits

usually  cannot be made.  When amplifier adJust
m ents  are  required, the entire  amplifier should
be  calibrated.

In addition, if either the 150

volt supply or the high voltage power supply is
adjusted, the

entire

instrument must be

c alibrated.

you find that a circuit is out of calibration ,

but  you  are  not  aware  of  which  particular
adjustment  will  correct  the  difficulty ,  it  is
usually  best  to  calibrate  the  entire  circuit.

E q u i p m e n t Required

The following equipment or its equivalent

is necessary for a complete calibration of the

Type 570 Os cilloscope.

1 . DC voltmeter (sensitivity of at least 5000

ohms per volt) with corrected readings within

1 % for 100 , 1 50 , 300 and 400 volts and within 3%

of 1700 volt s . Be sure your meter is accurate;

few portable test meters have the required

accuracy, particularly after a period of use.

2. Accurate rms- reading ac voltmeter , 0 - 150

volts (0- 250 or 0 - 300 volts for 2 1 0 - to 250-volt
operation).

3 . Variable autotransformer, having a rating of
at least 500 watts.

4 .   Oscilloscope,  Tektronix  Type  503  or  504.
If  a  Type  503  or  504  Oscilloscope  is  not
available,  it  will  be  necess ary  to  substitute
an os cilloscope  with the following specifications :

( 1 ) calibrated vertical deflection factors from

. 0 1 to 10 volts per division and (2) bandpass of

dc to 500 kilocycle s .

5. Jumpers , 6 inch with banana plugs .

6 . Socket adapter plate, miniature 9 pin.

7 . 6U8 vacuum tube.

8. Alignment tool. See figure 5 - 1 .

Jaco

No. 1 25 Tektronix Part No. 003-000

Fig. 5-1.

Tool required tor calibrating the Type

570