Power Supply Voltage Adjustments; Modulation Meter Adjustment; Modulation Meter - HP 608E Operating And Service Manual

Mode1608E/F Section V
5-31. POWER SUPPLY VOLTAGE
ADJUSTMENTS. M2 CALIS.
RI04
-165 VOLT ADJ.
R80
+225YOLT
ADJ.
R71
b. Set signal generator controls as follows:
a. Connect an adjustable transformer to control
line voltage applied to the signal generator.
5-33. Because of the interdependence of these power
supplies, the -165 volt regulator must be set first, the
+225 volt regulator second, and the +25 and -6.3 volt
regulators last. After adjusting any of these regu-
lators, check the output voltage of each other regulator
to
be
sure it is stm within specified tolerances.
max. ccw
max. ccw
centered
high end stop
max. cw
CW
max. cw
ON
. . OFF
MODULATION control
RF OUTPUT
FINE FREQ
Frequency .
AMPL TRIMMER
MODULATION selector
Altenuator . .
Power switch
XTAL CAL
5-32. There are four adjustabledcoperatingvoltages:
-165, +225, +25, and -6.3 volts. Adjustthesevoltages
only if proven by accurate measurement to be outside
the tolerances specified below and only if voltage error
is not caused by excessive current drawn through the
regulator or by inadequate voltage supplied to the reg-
ulator from the power supply rectifiers.
c. Adjust line voltage transformer to deliver 115
(or 230) volts. Be sure 115/230 volt switch is set
correctly.
Figure 5-13. Location of P0we:- ~.·;,~l:· :':ld
Modulation Meter Adjustments
d. Measure, and
if
necessary, adjust the following
voltages:
Voltage
Adjustment
(Figure 5-13)
-165 + 5 R80
+225:! 5 R71
+25 .± 1 Replace CR28
if
necessary
-7.2±G.3 Replace CR20
if
necessary
c. Adjust mechanical zero-adjust screw clockwise
until pointer is at left of meter zero and moving towards
meter zero; stop adjustment when meter needle is
exactly at zero.
If
needle overshoots, repeat ad-
justment.
d. Carefully adjust mechanical zero-adjust screw
a few degrees to free screw from meter suspension.
If pointer moves off zero, repeat step c.
e. Remove shorting lead from meter terminals.
5-36. ELECTRICAL ZERO. Adjust electrical zero
as follows:
5-34. MODULATION METER ADJUSTMENT.
5-35. MECHANICAL ZERO. Adjust mechanical zero
as follows:
a. Adjust RI06 (front-panel ZERO adjustment) fully
clockwise. PERCENT MODULATION meter should
indicate at least 30% mooulation.
a. Set MODULATION selector to CWo
b.
Connect shorting lead across PERCENT MODU-
LATION meter terminals.
b.
Adjust line voltage from 102 to 128 (or 204 to
256) volts. PERCENT MODULATION meter indication
should not change more than .±10% of full scale.
5-13