Tektronix WFM 601A, Service Manual

Page: 72 / 368

Performance Verification
4–8
WFM 601A, WFM 601E, & WFM 601M Service Manual
d. CHECK – by adjusting the HORIZ POS control that both ends of the
waveform can be positioned past the center of the CRT.
e. Turn off the MAG Sweep.
5. Calibrator Timing Frequency
REQUIREMENT – Frequency: 100 kHz 0.1%.
a. Set the Frequency Counter Timing to 1
m
s.
b. Connect an X1 probe from the frequency counter to the ribbon cable side
of A3R274 (Main board). See Figure 5–6 on page 5–16 in the Adjust-
ment Procedure section.
c. Connect the probe ground to the metal shield adjacent to A3L5 on the
Main board.
d. Adjust the frequency counter settings for a stable readout.
e. CHECK – that the counter reading is 100 kHz 0.1 kHz.
f. Remove the ground connection and the frequency-counter probe from
A3R274.
6. Timing and Linearity
REQUIREMENT – Sweep Timing Accuracy: 5
m
s/div (1 Line), 10
m
s/div
(2 Line), 0.2
m
s/div (1 Line + MAG), 1.0
m
s/div (2 Line + MAG), 1%.
Sweep Linearity: 1 Line and 2 Line sweeps unmagnified or magnified, 1%.
a. Press the WAVEFORM display button.
b. Enter the CONFIG menu and select CALIBRATE.
c. Select CAL SIG ON. Ensure that the VAR GAIN bezel button is OFF.
d. Push the SWEEP button several times to select the 2-Line Sweep mode.
The LINE indicator is on and the time base readout indicates 10
m
s/div.
e. Press the CRT button and adjust the Scale bezel knob to increase scale
illumination to a useful level.
f. Press the Clear Menu button.
g. Use the VERT POS and VERT HORIZ knobs to position the calibration
waveform on the horizontal graticule line for measurement.
h. CHECK – for one cycle of the calibrator signal per major division
0.5 minor division over the 10 major graticule divisions.
i. Turn on the MAG Sweep.