Adjustment And Calibration Procedure; Meter Mechanical Zero Set; Power Supply And Bias Adjustments - HP 333A Technical Manual

Model 333A/334A
c. Set Signal Generator controls as follows:
FREQUENCY. . . . . . . . . . . . . . . l Mc
MODULATION SELECTOR . . . . . . . EXT
ATTENUATOR/VERNIER . . . . . 3.O VOLTS
Modulate Signal Generator output 30% with a 1000
cps signal using a 203A Function Generator or
comparable oscillator.
d. Adjust Distortion Analyzer SENSITIVITY Select-
or and VERNIER control for 0 DB reference.
e. Switch FUNCTION selector to DISTORTION. Ad-
just BALANCE controls and Frequency Dial for null
indication.
f. Distortion shall be more than -40 db down.
5-22. ADJUSTMENT AND CALIBRATION
PROCEDURE.
5-23. The following is a complete adjustment and cali-
bration procedure for the 333A and 334A. Before
proceeding with these adjustments, the Performance
Checks should be performed to determine whether
adjustments are necessary, If your instrument does
not meet the test limits specified in the following
steps, refer to Troubleshooting Procedure, Paragraph
5-33. Adjustment locations are shown in Figure 5-8.
5-24. The Adjustment and Calibration Procedure is
performed with the ac power cord connected to nomi-
nal line voltage ( 115 v/230 v) 50 to 1000 cps, MODE
* Referenced to -25 volt supply; -25 volt supply must be adjusted first.
* * This voltage has been adjusted for optimum distortion performance. Do not readjust unless A2Q1 is changed.
‡ This voltage has been adjusted for optimum distortion performance, Do not readjust unless A3Q4 is changed.
Paragraphs 5-23 to 5-27, Figure 5-7 and Table 5-6
No.
Connector, male
1
Connector, male w/insulator
2
Lug, terminal 90°
3
Resistor, 100 K Ω, 1/2
4
metal film
Resistor, 600 K Ω, 1/4 w, O. 5%
4
metal film
5 Washer, int. lock
6 Spacer, 6-32 threaded
7 Shield
8 Screw, bind. head, 6-32 x 1/4 in
Figure 5-7. Shielded Load Assembly
switch to MANUAL, HIGH PASS FILTER to OUT, and
NORM RF DET switch to NORM, unless otherwise
specified.

5-25. METER MECHANICAL ZERO SET.

5-26. The meter is properly zero-set when the pointer
rests over the zero calibration mark on the meter
scale and the meter is in its normal operating environ-
ment and turned off, Adjust the zero-set, if necessary,
as follows:
a. Rotate mechancial zero-adjustment screw clock-
wise until meter pointer is to the left of zero and mov-
ing upscale toward zero.
b. Continue to rotate adjustment screw clockwise;
stop when pointer is exactly at zero. If the pointer
overshoots zero, repeat step a.
c. When pointer is exactly on zero, rotate adjust-
ment screw approximately 2 degrees counterclockwise.
This is enough to free the zero adjustment screw from
the meter suspension. If pointer moves during this
step, repeat steps a through c.

5-27. POWER SUPPLY AND BIAS ADJUSTMENTS

a. Refer to Table 5-6 for the power supply and bias
measurement points, adjustments, voltage limits and
line regulation specifications.
Table 5-6. Power Supply Adjustments
TM 11-6625-1576-15
-hp- Part No.
Description
, 5%
W
Section V
1251-0174
1251-0175
0360-0042
0758-0053
0757-1037
2190-0007
0380-0058
1251-1073
2470-0001
5-7