Tektronix 502A Instruction Manual page 47

10. NORM MAG REG S
Turn the TRIGGERING LEVEL to RECURRENT and place
the HORIZONT L DISPL Y switch in the X20 position. Posi ­
tion the start of the upper trace under the vertical centerline
of the graticule. Rotate the HORIZONT L DISPL Y switch
to NORM L and adjust the NORM M G REGIS Control so
that the start of the sweep again lies under the vertical
centerline of the graticule. Repeat adjustments 9 and 10
until both are set correctly.
11. Check Timing from .1 millisecond
through 5 seconds
From the Type 180 apply time markers to the
both beams as indicated below.
and check for proper display.
TIME/CM TIME M RKERS
1 mSEC
1 MILLISECONDS
2 mSEC
1 MILLISECONDS
5 mSEC 5 MILLISECONDS
10 mSEC
10 MILLISECONDS
20 mSEC 10 MILLISECONDS
50 mSEC
50 MILLISECONDS
100 mSEC 100 MILLISECONDS
200 mSEC 100 MILLISECONDS
500 mSEC 500 MILLISECONDS
1 SEC 1 SECONDS
2 SEC 1 SECONDS
5 SEC 5 SECONDS
100 MICROSECONDS
.1 mSEC
Disconnect Time Markers.
12. Fast Sweep Rate Adjustments
Turn the TIME/CM Control to 10 μ SEC and the TRIGGER ­
ING LEVEL to RECURRENT. Set the input switch of the test
oscilloscope to DC.
Connect a probe from the test oscilloscope to pin 3 of
V 1 83 and adjust C311 for a flat base on the holdoff
waveform. This is just a preliminary adjustment of C31 1.
A.
Fig. 5-6. Adjustment of C311.
waveform B is obtained on the test oscilloscope.
input of
djust for a stable display
DISPL Y
1 marker/cm
2 markers/cm
1 marker/cm
1 marker/cm
2 markers/cm
1 marker/cm
1 marker/cm
2 markers/cm
1 marker/cm
1 marker/cm
2 markers/cm
1 marker/cm
1 marker/cm
Waveforms A and C result from improper settings of C311.
Calibration Procedure — Type 502A
djustment of the faster sweep rates is indicated in the
chart below. The 1 μ SEC and the 5 μ SEC timing adjustments
will interact and therefore will have to be rechecked several
times. pply time markers to both
display.
TIME/CM TIME M RKERS
FROM TYPE 180
10 μ SEC 10 MICROSECONDS
20 μ SEC
10 MICROSECONDS
50 μ SEC 50 MICROSECONDS
1 μ SEC
1 MICROSECONDS
2 μ SEC 1 MICROSECONDS
5 μ SEC 5 MICROSECONDS
Disconnect Time Markers.
13. EXT HOR Z AMP DC BAL
Rotate the HORIZONT L DISPL Y switch through the EXT
VOLTS/CM positions and adjust the EXT HORIZ
Control so that there is no horizontal shift of the spots as
the HORIZONT L DISPL Y switch is rotated.
14. Checking External Gain and Attenuator
pply 5 volts to the EXTERN L connector from the
TUDE C LIBR TOR. With the HORIZONT L DISPL Y switch
set in the 2 EXT. VOLTS/CM position check for a deflection
of 2.5 cm. Check the other positions of the display switch
for the proper deflection. Return the HORIZONT L DISPL Y
switch to the NORM L position and disconnect the jumper.
The following adjustments apply to both of the
vertical amplifiers. Complete the calibration of one
amplifier before proceeding to the other.
B.
Capacitor C311 should be adjusted so that
inputs and trigger the
DJUST OR
CHECK
djust C160C for
1 marker/cm
Check for 2
markers/cm
Check for 1
marker/cm
djust C31 1 for
1 marker/cm
Check for 2
markers/cm
djust C160
1 marker/cm
MP DC B L
NOTE
C.
for
MPLI ­
5-5