SECTION IV
MAINTENANCE
4-1 OUTPUT PULSE ANALYSIS
The output pulse of the Model 2 12A Pulse Generator will be divided into
three parts: the leading edge, the top or body, and the trailing edge.
Each part is affected by different circuits. If a defect appears on apart
of the output pulse, it will generally indicate the circuit at fault. Each
part of the pulse is described separately and the list of symptoms in the
trouble shooting chart follows the same general order.
Leadin Ed e -- V6, the rstart' thyratron, "urns ont the output pulse.
?7+-- 1 7B trrggers V6 and V6 forms the leading edge of the output pulse.
Only the circuits of V6 and V107B are responsible for the condition of
the leadin ed e of the output pulse. A defect that appears on the lead-
&uch as jitter and slowness, is the direct result of a de -
F- ective tube, crystal diode, or other component in the circuits of V6
and VlOTS. See items 2,3, and 4 of trouble shooting chart.
Overshoot -- Overshoot occurs to a greater degree on the leading edge
of the pulse than on the trailing edge. Overshoot greater than specified
is usually caused by leads used for external connections to the pulse
generator.
Very minor overshoot coming from the pulse generator is caused by com-
ponent construction, wiring and lead length within the instrument, Vl OA
compensates for this overshoot on the leading edges of both negative and
positive output pulses. This tube amplifies a portion of the rise time
from thyratron V6 and couples it to the plate circuit of V11 for negative
pulses and to the cathode circuit for positive pulses. The degree of com-
pensation is controlled by adjustable ceramic capacitors C 1 1 and C22.
The setting of each capacitor affects that of the other, The final adjust-
ment is accomplished by alternately adjusting the two capacitors while
observing both positive andnegative pulses. Adjust for optimum pulse
shape. C11 is generally set near minimum capacity. C22 is used for a
greater portion of the adjustment. See item 5 of the trouble shooting
chart.
To of Pulse -- When V6 is triggered, it generates a pulse limited in
-time plate voltage supplied to this tube. To protect Yb,
the supply is constructed momentarily to stop power delivery approximate-
ly 11 micraseconds from the time V6 fires. V6 is then extinguished and
will not fire until re-triggered.
The pulse generated by V6 is very coarse and contains peaks in excess of
500 volts. Clippers V7 and V9 clip the amplitude to between 250 and 350 |
ACEC
HEWLETT-PACKARD
