HP TM 11-6625-2779-14&P - Manual (Page 42)

Section V Model 3555B
CARRIER 600 and repeat the above
procedure. Between 1kHz and 10kHz, the
balance must be greater than 70dB.
Between 10kHz and 100kHz, the balance
must be better than 60dB. Between 100kHz
and 600kHz, balance must be better than
40dB.
5-14. ADJUSTMENT AND CALIBRATION
PROCEDURE.
5-15.
The following is a complete adjustment and
calibration procedure for the Model 3555B. These
adjustments should be performed only after it has been
determined by the performance checks that the set is not
operating within its published specifications.
5-16.
POWER SUPPLY CHECK.
5-17. Before attempting the following calibration
procedures, first check the power supply voltage to be
sure that it is correct and that the ripple voltage is not
abnormal. To do this perform the following steps.
NOTE
Calibration of the 3555B should be
performed with the set operating from
the internal battery except for the
power supply ripple check in the
following steps. Operate the set from
the ac power source long enough to
make this check and then return the
set to internal battery operation. This
is accomplished by changing the
position of the slide switch mounted
on the side of the set. When operating
from the battery, disconnect the ac
power cord from the set.
a.
Remove the set from the case and connect
the 3440A/3445A dc voltmeter between the -
20V supply and ground. The negative side
of A3C34 is a convenient place.
b. Turn the set on. The 3440A/3445A should
indicate -20 volts
±
1.0V.
c. Connect the 400FL AC Voltmeter to the
negative side of A3C34 and measure the
ripple voltage. The maximum allowable
ripple is 200uV rms.
5-18. 75 UNBAL CALIBRATION.
a.
Connect the 654A and 3440A/3445A as
shown in Figure 5-2 and set the 3555B
controls as follows:
FUNCTION ................ 75 UNBAL
INPUT..................... TMS, TERM
RANGE ..........................+10dBm
b. Set the 654A frequency to 10 kHz, 75
UNBAL, and adjust the output level for 866
mV (+ 10 dBm) indication on the
3440A/3445A.
c. Set the 654A meter for a reference indication
and be sure to maintain this indication
throughout the following procedures unless
otherwise instructed. Disconnect the
3440A/3445A voltmeter.
d. Change the 654A to -50dBm and change the
3555B RANGE switch to -50dBm.
e. Disconnect the 3440A/3445A, the 11094A
termination and the cable. Connect the
654A output directly to the 3555B input.
f. Adjust A3R43 for 0dBm indication on the
3555B meter.
g. Change 654A frequency to 3MHz
maintaining the reference established on the
654A meter.
h. Adjust A3C8 for 0dBm indication on the
3555B meter.
5-19. ATTENUATOR CALIBRATION.
a.
Remove the FUNCTION board and replace it
with the test board supplied with the set.
b. With the equipment and controls set as in
the preceding check, change the 3555B
RANGE to 40dBm and change the 654A
attenuator to -40dBm. Change the 654A
frequency to 100kHz.
c. Adjust A2C12 for 0dBm indication on the
3555B meter.
d. Change the 3555B RANGE switch to
-30dBm and change the 654A attenuator to -
30dBm. Adjust A2C7 for 0dBm indication on
the 3555B meter.
e. Change the 3555B RANGE switch to
-20dBm and change the 654A attenuator to -
20dBm. Adjust A2C4 for 0dBm indication on
the 3555B meter.
f. Change the 3555B RANGE switch to
+10dBm and change the 654A attenuator to
+10dBm. Adjust A2C1 for 0dBm indication
on the 3555B meter.
g. Check the frequencies listed in Table 5-2 for
the tolerance indicated. If any of the checks
in Table 5-2 do not meet the indicated
tolerances, repeat steps b through f.
5-20. FUNCTION CALIBRATION.
a.
Remove the test board from the set and
install the function board assembly. Connect
the 654A balanced output to the 3555B
balanced input terminals. See Figure 5-5.
Set the 3555B controls as follows:
FUNCTION........ CARRIER, 600 BAL
INPUT ........................... TMS, TERM
RANGE ................................ -50dBm
b. Set the 654A frequency to 10kHz and adjust
the output attenuators for -5OdBm output
level, using the 600 BAL output function.
5-8