Tektronix 3B5, Instruction Manual

Page: 124 / 187

Calibration — Type 3B5
Fig. 6-21. Typical CRT display showing correct 10-nano$econd
timing.
20 ns Cal 50 ns Cal
(B)
Fig. 6-20. (A) Typical CRT display showing correct 50-nanosecond
timing, (B) Location of 50 and 20 ns adjustments (Time-Base
Board), (C) Typical CRT display showing correct 20-nanosecond
timing.
c. ADJUST —C547 and C551 (see Fig. 6-18A) slightly for
optimum timing and linearity. (Note: readjust only if out­
side the tolerances listed in step b).
d. If adjustments are made, recheck step 19.
21. Check Normal and Magnified Timing
Accuracy
a. Connect the time-mark generator trigger output con ­
nector to the EXT TRIG INPUT connector with a 50-ohm BNC
cable.
b. Set the DELAY dial to 0.00.
First Check timing between first and Ninth
graticule ninth graticule lines graticule
line line
Fig. 6-22. Typical CRT display when checking timing accuracy (1 /is
to 50 ms). Waveform shown was taken with MANUAL TIME/DIV
switch set at 1 ms and DLY'D SWP MAG switch set to OFF.
6-20