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d.
Phase Detector Peaking (L203)„
(1)
Test equipment:
20 kQ-per-volt VTVM (or multimeter).
(2)
Procedure:
a.
Remove the cabinet.
b„
Adjust the Model 75D front panel controls in accordance with
Table 4.
Co
Zero balance the bridge as described in paragraph 3.5„
d.
Adjust the VTVM to measure approximately -1 .5 V.
e.
Connect the VTVM prods between the white terminal on the
preamplifier printed circuit board and chassis ground.
f.
Adjust the CAPACITANCE control until the NULL INDICATOR
pointer is at midscale.
g„
Loosen the locking nut on L203 by turning ccw.
h.
Adjust L203 maximum indication on the VTVM.
i„
Tighten the L203 locking nut by turning cw,
j.
Remove the VTVM.
e.
DC Amplifier Balance (R302).
(1)
Test equipment:
None.
(2)
Procedure:
a.
Remove the cabinet.
b.
Adjust the Model 75D front panel controls in accordance with
Table 4.
Co
Set the MULTIPLY C switch to 0.0001 ,
d.
Zero balance the bridge as described in paragraph 3.5.
e.
Set the meter switch to ZERO CENTER.
f.
Adjust R302 until the NULL INDICATOR pointer rests exactly at
the midscale increment,
f.
Internal Phase Shift Alignment (LI 04).
(1)
Test equipment:
None,
(2)
Procedure:
a.
Remove the cabinet.
b.
Adjust the Model 75D front panel controls in accordance with
Table 4.
Co
Set the MULTIPLY C switch to 0.01.
do
Set the DIVIDE G/MULTIPLY R switch to 10.
e.
Zero balance the bridge as described in paragraph 3.5.
75 D
b-370
64
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