Specifications

Section IV. FINAL ADJUSTMENTS
41. General
Final adjustment of the TS-1777/VRM-l
must be performed after major repair,
parts replacement, or extensive alignment
of individual plug-in assemblies. The final
adjustment procedures can also be used
as a quick check to see if the TS-177/
VRM-1 circuits are properly adjusted.
42. Test Equipment and Special. Tools
Required
a. The following chart lists test equip-
ment required for final adjustment of Test
Set, Radio AN/VRM-l. Associated techni-
cal manuals are also listed.
b. The special tool required for final
adjustment is Cable No. 10 (fig. 21).
43. Final Adjustments
Adjust the AN/VRM-l as directed in the
procedures below, in the order given. Fig-
ure 23 shows the location of the final
adjust ments.
Note: All voltages are measured to chassis un-
le SS otherwise specified.
a. Connection Data (fig. 22). Perform
the following procedure prior to final ad-
justments:
(1)
(2)
Remove the TS-1777/VRM-l front
panel and chassis from the case
(para 36a).
Connect the PP-2309/U, CX-4720/
VRC,
MT-1029/VRC, CX-7899/
VRM-1,
and TS-1777/VRM-l
(para 32).
(3)
(4)
(5)
Connect the TS-443/U across the
output terminals of the PP-2309/
u.
Set the PP-2309/U for O-volt dc
output, and turn it on.
Set the TS-1777/VRM-l ON-OFF
switch to ON.
Caution: Always remove the test
signal to the test probe before re-
moving power from the TS-177/
VRM-1.
b. Line Voltage Sensing Circuit (fig.
33).
(1)
(2)
(3)
(4)
(5)
—
Increase the PP-2309/U output for
an indication on the TS443/U of
approximately 5 volts dc.
Measure the dc voltage at the emit-
ter of transistor Q7806 (ungrounded
side of potentiometer R7816); use
the ME-26B/U. Adjust potentiom-
eter R7816 for an indication of less
than +2 volts dc.
Increase- the output of the PP-
2309/U for an indication on the
TS-443/U of 21.5 volts dc.
Adjust potentiometer R7816 in the
increasing voltage direction until
RED indicator lamp DS7901
switches on (as indicated by a sud-
den drop in voltage at the emitter
of Q7806). This action should occur
at approximately +12 volts dc.
Reduce the output of the PP-2309/
U to O volt dc; then increase it
slowly until RED indicator DS7901
lights. (Note a sudden drop in volt-
age measured at the emitter of
Q7806.) The PP-2309/U output
voltage as indicated on the TS-
443/U, required to light RED indi-
cator lamp DS7901, should be 21.5
volts dc. Readjust the potentiom-
eter R7816 as necessary to assure
this condition.
c. Voltage Supply Limits Sensing Cir-
cuit (fig. 33). Connect the equipment as
shown
(1)
(2)
in figure 24.
Turn the TS-1777/VRM-l selector
switch to position 8.
Increase the output of the PP-
2309/U to 26 volts dc.
33