Sect. N Page 22 Model 618B
11) Set the PULSE RATE control to 40 pps, with 1) Connect the RF OUTPUT through a crystal
the other controls remaining unchanged. Set detector to the vertical input of an oscilloscope
oscillator to 40 cps. having an accurately calibrated sweep.
12) Adjust R117 so that the generated pulse rate
2) Connect the SYNC OUT connector to the SYNC
is 40 pps.
connector on the oscilloscope.
13) Set the SYNC SELECTOR to X10 and check
the calibration of the PULSE RATE dial in vicinity 3) Set the PULSE WIM'H control to 10 micro-
of 40. R117 can be readjusted to improve cali- seconds.
bration accuracy if desired.
4) Adjust R156, Figure 4-6B and 4-13, so that
14) Refine the above adjustments as desired or the width of the generated pulse is 10microseconds
for best overall accuracy.
as measured on the oscilloscope.
5) Set the PULSE WIDTH control to 1 microsecond.
4-18 CALIBRATING THE PULSE DELAY DIAL
6) If necessary, slip dial to read 1 microsecond.
Replacing V107 may lessen the accuracy of the
PULSE DELAY dial. After replacing V107,' the
7) Repeat steps 3, 4, 5 and 6 for best overall
following procedure can be used to adjust thedelay
calibration accuracy.
calibration; however, the calibration of the PULSE
DELAY dial is intended only to be approximate.
8) The width of the rf pulse will vary approxi-
mately 1/4 microsecond as the generator is tuned
1) Connect the DELAYED SYNC OUT terminal
through its rf range. The above adjustments can
to the vertical input of an oscilloscope having an
be made for best accuracy at any desired rf
accurately calibrated sweep.
frequency.
2) Synchronize the oscilloscope from the SYNC
OUT connector.
4-20 LUBRICATION
3) Set PULSE DELAY control to 300 microseconds.
It is not expected that the mechanical parts of the
4) Adjust R133, Figure 4-6B or Figure 4-13, to signal generator will require lubrication within
give a delay of 300 microseconds as measured on the first year of operation. Moving parts such
the calibrated oscilloscope screen. ' as the attenuator and power monitor rack gears
are lubricated at the factory with Lubriplate 105V,
5) Set PULSE DELAY control to 3 microseconds Fiske Brothers Refining Co., Newark, N. J. The
as read on oscilloscope screen. If necessary, frequency drive gears behind the front panel are
slip the PULSE DELAY dial on its shaft to make lubricated with a mixture of Shell Tonna Oil G and
calibration accurate. The delay is indicated by Molykote Type M. The drive mechanism shown
the interval between the start of the oscilloscope in Figure 4-11 is lubricated with ShellTonna Oil G.
'
trace and the leading edge of the DELAYED SYNC Do not lubricate cavity plunger rods.
OUT pulse.
6) Repeat steps 3 and 4 for best overall cali-
4-21 REPLACING REFLECTOR POTEN-
bration.
TIOMETER R174
To replace potentiometer R174 on the frequency
drive casting, refer to Figure 4-14 and proceed
4-19 CALIBRATING THE PULSE
as follows:
WIDTH DIAL
Replacing Vlll may lessen the accuracy of the 1) Disconnect blower tube at cavity.
PULSE WIDTH dial. After replacing the V111,
the following procedure can be used to calibrate 2) Remove the four flat head screws on each side
the PULSE WIDTH dial: of the front panel that hold the panel assembly to |
ACEC
HEWLETT-PACKARD
