Tektronix 4010 Maintenance Manual page 66

Adjustment-4010 Maintenance
c. Press PAGE and then press MAKE COPY. Adjust the
oscilloscope triggering to obtain a stable display. The pulses
resulting from scanning an empty screen should appear as in
Fig.4-15A.
d. Preliminary adjustment. Adjust Hard Copy Damping
(R21 on the Hard Copy TARSIG Amplifier board, Fig.
4-13) for maximum negative pulse amplitude with
minimum ringing as in Fig. 4-15A.
e. Press 8 to fill the display. Then press MAKE COpy
and observe the oscilloscope for a waveform as in Fig.
4-158.
f. Readjust Hard Copy Damping to obtain maximum
negative-going pulses with minimum ringing. The
negative-going ringing should be half or less of the
amplitude of the main negative-going pulses. See Fig.
4-158.
(A) Waveform resulting from scanning an empty screen
(8) Waveform resulting from scanning a full screen 1183-20
Fig. 4-15. Hard Copy Damping waveforms; 0.2 V/division vertical,
0.5 Ils/division horizontal.
4-20
20. (4010-1
Only) Hard Copy Threshold
Check/Adjustment (R35-Hard Copy Threshold,
on Hard Copy T ARSIG Amplifier Board in display
unit)
a. The oscilloscope remains connected as in step 19.
b. Connect a probe from channel 2 of the oscilloscope
to TP30 on the Hard Copy TARSIG Amplifier board (Fig.
4-13). Connect the probe ground lead to ground.
c. Set the oscilloscope for alternate trace operation, with
each channel set for 0.2 V Idivision; sweep rate 0.5
!lsi
division. (Neither channel should be inverted.) Set both
input switches to ground and set both traces to the same
reference point. Then switch both input switches to DC.
d. Press PAGE and 8 to refill the display.
e. Press MAKE COPY and observe the oscilloscope
display for a waveform as in Fig. 4-16. The channel 1
display (TP32) should be above the channel 2 display, and
the written pulses should overlap for approximately 113 of
the distance between the two traces. Ringing should remain
well separated. (Trace separation will probably end up
being between 0.4 and 0.8 V.)
f. Adjust Hard Copy Threshold (R35, Fig. 4-13) to
obtain a display as in Fig. 4-16.
Fig. 4-16. Hard Copy Threshold Waveform; 0.2 V/division vertical,
0.5 V/division horizontal.
®