Tektronix 114 - Page 21

Maintenance and Calibration — Type 114
Fig 4-8. Control settings for adjusting the 1 microsecond period capacitor .
7. Adjust 1 microsecond period capacitor
C115F
a. Sot the Type 114 PERIOD control to 1 µ S, the WIDTH
control to 100 nS, and both PERIOD and WIDTH — VARI 
ABLE controls to CAL (see Fig. 4-8).
b. Set the Type 547 TIME/CM (B ) switch to 1 µ SEC. Push
in the PULL TO INVERT switch on Channel 2 of the Type
1A1.
c. Set the Type 180A to deliver 1 microsecond markers .
d. Using the Type 1A1 POSITION controls, put the peak
of the first pulse from the Type 114 to some reference point
on the first pulse from the Type 180A (see Fig. 4-9).
e. Adjust capacitor C115F (see Fig. 4-10) so that the peaks
of the pulses from the Type 114 occur at the same point on
each succeeding pulse from the Type 180A as shown in Fig.
4-9. Allowable error is 3%, but it is possible to adjust
much closer than this.
8. Check period accuracy, 10 mS to 1 µ S
a. Set th e Type 114 PERIOD control to 10 mS and th e
WIDTH control to 10 µ S.
Fig. 4-10 Location of 1 microsecond period capacitor C115F.
b. Turn the Type 1A1 MODE switch to ALT and pull out
the Channel 2 PULL TO INVERT switch
c. Set the Type 180A to deliver 10 millisecond markers.
d. Set the Type 547 TIME/CM |B) switch to lOmSEC and
adjust the TRIGGERING LEVEL control for a stable display.
e. Check for horizontal alignment between the two sets
of markers (see Fig. 4-7). Horizontal alignment should be
within 3%.
4-7