Tektronix TYPE 109, Instruction Manual

Page: 39 / 56

Calibration— Type 109
C o nnecto r end C o n ne cto r end
o f R 7 5 7
R eed an d
co n tact a s s y .
M a g n e t
M a g n e t H o ld-D o w n
Screw s
F ig . 6 - 7 . M e rc u ry p u lse r a s s e m b ly . Test p o in ts fo r step 5h are
sh o w n a ls o .
(2) Loosen the magnet hold-down screws (see Fig. 6-7)
and carefully move the magnet closer to or aw ay
from the reed and contact assembly. At the same
time, shift the magnet slightly from side to side.
N O TE
Positioning the m agnet too close to the reed
tends to promote b rid g in g ; moving it too far aw ay
causes skip p in g; i.e., only one side is contacting.
M oving the m agnet too fa r to one side or the
other can cause the reed to stop com pletely.
Position the magnet so the reed vibrates freely
and buzzes smoothly. At the same time, adjust
the FREQUEN CY control until a steady waveform
display is obtained. By carefully positioning the
magnet and adjusting the FREQUENCY control
together, find the point where a steady wavetorm
with all the desirable characteristics explained
earlier are obtained.
(3) Then hold the magnet at that position, and care­
fully tighten the hold-down screws without disturb­
ing the location of the magnet.
(4) As a final touch-up, readjust the FREQUENCY
control a few degrees in either direction to find
the optimum point where the best waveform is
obtained with least jitter over the line-voltage op­
erating range.
i. Disconnect the mercury switch tester leads and the
1 0 X probe from the Type 109.
j. Check that the autotransformer is set for an output
of 117 (or 234) volts.
5. Check Output Amplitude
a. Set the Type 109 AMPLITUDE control to 50 and the
VO LTAG E RAN GE switch to 50; set the PULSE POLAR­
ITY switch to + .
b. Connect a 50-ohm 20-nsec cable to the 50 Q CHG.
LINE 1 and 50 Q CH G . LINE 2 connectors.
c. Connect a 8 " 50-ohm terminated pigtail to the 50 Ü
OUTPUT connector.
d. Set the conventional test oscilloscope Volts/Cm switch
to 2, the Time/Cm switch to .1 fj, Sec, and the 5X Mag.
switch to O N (or 5X).
e. Connect the 10X probe tip to the pigtail termination,
and the ground strap from the probe to the cable
shield.
f. Adjust the triggering and position controls on the
oscilloscope to obtain a stable display within the
graticule area.
F ig . 6 - 8 . C h e ck in g p ulse d u ra tio n a n d a m p litu d e . S w e e p ra te is
2 0 n se c/cm .
TABLE 6-4
VO LTAG E
RANGE
Switch
Setting
PULSE
POLARITY
Switch
Setting
Oscilloscope Controls
Waveform
Amplitude
(peak)
Volts/Cm
Switch
Setting
Trigger
Slope
Switch
50
+
2
+
+ 50 volts,
± 3 %
50 —
2 —50 volts,
± 3 %
5 —
.2 — —5 volts,
± 3 %
5
+
.2
+
+ 5 volts,
± 3 %
0.5
+
.05
+
+ 0 .5 volt,
± 3 %
0.5
—
.05
—
—0.5 volt,
± 3 %
EXT. PWR.* + or - .2
+
+ 5 volts,
± 1 0 %
*For this check, turn off the Type 109, connect a 12" jump­
er lead from the + 1 0 V test point (see Fig. 6~3) to the con­
nector end of R752 (see Fig. 6-7) and turn on the Type 109.
Check waveform amplitude and duration. Then, repeat the
check by connecting the jumper lead between the same
+ 10 V test point and the connector end of R757 (see Fig.
6-7).
(?)
6-5