Sect. IV Page 19
a vertical deflection sensitivity of 1 volt per centi- No. 15OA-65 E, L or LR only. See Figure 4-7B.
meter.
a. Connect a dc VTVN between ground and pin
7) Connect test oscilloscope probe to junction of R65 2 of V10. The voltmeter indication will swing
and arm of S2 TRIGGER SLOPE switch (use ac coup- between approximately -40 and -15 volts.
ling). This point can be identified as the connector
approximatelymidway between tubes V9 and V17 to b. Adjust R88 to obtain -15 volts at the end of
which a greenwire from the TRIGGERSLOPE switch the sweep. Ifunable to setR88, rotate R135
is connected. If high frequency oscillations are until R88 may be set properly.
present, rotate R66 maximum counterclockwise.
4) Connect the dc VTVM between ground and pin 8
8) Refer to Figures 4-7 and 4-8. Adjust potentio- of V15. The violet wire terminated above V15 con-
meter R66 and R72 for pips vertically spaced ex- nects to pin 8.
actly 1 volt apart on the displayed sine wave. In
addition, the pips must be exactly 0.5 volt above and 5) The voltmeter indication will rise and fall with
below the center of the wave. The upper pip must be the sweep. Adjust R122 or R135 (see Figure 4-7)
on the positive slope portion of the sine wave and until the end of the sweep occurs between -110 and
the lower on the negative slope. -115 volts.
These two controls interact but pip vertical separa- 6) Set the SWEEP TIME/CM to. 1 MICROSECONDS,
tion is primarily controlled by R66 and vertical SWEEP VERNIER to CAL. and HORIZ. SENSITI-
position of both pips by R72. Repeated adjustments VITY to X1. Connect the test oscilloscope to pin 8
of both controls may be required, of V15 through a low capacity probe andobserve the
sweep waveform, Adjust C40 for maximum undis-
torted amplitude. Undesirable distortion will ap-
pear at the most negative point on the waveform.
c. ADJUST SWEEP PRESET
1) Disconnect any external vertical input to oscil-
loscope. Set SWEEP TIME/CM switch to .1 MILLI-
S E C ONDS and SWEEP MODE control maximum
counterclockwise to PRESET. Set SYNC. selector
to INT.
2) Connect thedcvoltmeter +tween ground (+) and
pin 2 (-) of-V10. Slowly adjust R103 until the sweep
W
generamr begins to free-run. The voltmeter indi-
cation will increase, as R103 is rotated, to a maxi-
mum and ,then suddenly drop, when the sweep gen-
erator begins to free-run.
Figure 4-8. Sync Trigger Hysterisis
Limits
Repeat this several times and note the average
maximum voltmeter indication. The exact value of
I pips are not visible, set R66 as far clockvcl-je as
this voltage is not critical and will vary with indi-
possible without introducing oscillation and -then
vidual crhahcteristics of tubes V10 and V11.
slowly rotate R72 until the pips appear.
3) -Se1-R1'03 tb give a voltmeter indication exactly
1.5 volts less negarive than,the maximumnoted be-
B. ADJUST START-STOP TRIGGER AND
I SWEEP AMPLITUDE fore the sweep began to free--'run. For example: if
the maximum voltage noted was -37 volts, R103
should be set for -35.5 Volts.
1) With no inpyt-ts the oscilloscope, set the SYNC -
> -\ - . '-
selector to EXT. AC.
I. .. .-
b.' ADJUST SWEEP CALIBRATION
2) Set the SWEEP TJME/CM tp 2 SECONDSLCM *. -. . - , - ,.\
-. C.
and rotate SWEEP 'MODE maximum clockwise to
FREE RUN. , .- r -- x Physical- location of the variable capacitors for
.L ,,:. ' :,
Sweep Calibraiioi has varied with production. Com-
3) This step is for Sweep Generator Assemblies pare the configurations shown in Figure 4-9 to find |
ACEC
