HP 3336A - Page 143

Model 3336A/B/C Adjustments
| a. Remove cable W24 from A4J24.
mm |
b. Place jumper A4TP207, located midway between A4J2 and A4J23, in the test position
(away from the A3 assembly).
c. Place switches A4S1 and A482, located beside A4J2, to the test position (away from
the A3 assembly).
d. Connect an oscilloscope probe to A4TP AMP ZERO, located beside A4S1.
e. Set the 1740A in the the ground mode with .005 volts/div and adjust the vertical posi-
tion so that the trace is on the zero reference line in the center of the screen.
f. Put the oscilloscope in the dc mode and adjust A4R208 (labeled AMP ZERO - located
beside A4J23) for zero dc offset at A4TP AMP ZERO.
g. Return switches A4S1 and A4S2 and jumper A4207 to their normal positions.
5-27. Leveling Loop Bias Adjustment.
$-28. This procedure balances the bias current to the thermal converter.
Required Equipment:
Oscillscope -hp- Model 1740A
The 3336 must be on for 30 minutes before making this adjust-
ment,
a. Remove cable W24 from A4J24.
b. Ground test point A4TP201.
c. Connect the oscilloscope to test point A4TP AMP ZRO.
d. Set the oscilloscope to dc coupled, zero center, and 1 volt/div.
e. Adjust A4R212 (located between A4J40 and A4TP207) to center the signal and main-
tain it at the center of the screen.
f. Increase the sensitivity of the oscilloscope and readjust A4R212.
g. Repeat Step f until the oscilloscope is set at .005 Volts/div and the trace remains on
the screen for at least 5 seconds.
h. Remove the short from A4TP201 and reconnect W24.
Fo SOLUTE
5-29. 75 ohm Output Level Accuracy Adjustment. R A 5
X
i>
Y
AMPLITUDE
ACCURAC
7
—_
5-30.
This
adjustment
sets
the
absolute
amplitude
accuracy
of
the
unbalanced
outputs
by
accurately setting the minimum and maximum values of the amplitude’s dynamic range.
5-9