Wavetek 3000 Instruction Manual page 76

MAINTENANCE
Connect digital voltmeter
to chassis
MOD T .P . Set FREQ switch to VERNIER and
AM/FM Vernier control to maximum . Refer
to Figure 5-6 for control location and
adjust modulation board pot . (A) for a
+5 .00 V reading on voltmeter . Set AM/FM
Vernier to 0% AM ; the voltmeter should
indicate 0 V ±20 mV .
5 .3 .10
Meter Board Calibration - C315
To adjust OUTPUT meter, the unit must
rest on its bottom surface (normal op-
erating position) . Momentarily turn OFF
power to instrument and mechanically
zero OUTPUT meter with front-panel zero
adjust screw. The meter needle should
bisect dot at left end of meter scale .
Restore power to instrument and allow it
to stabilize .
Set front panel VERNIER fully ccw ; then,
adjust Meter Board pot . (B) until meter
needle again bisects dot at left end of
meter scale .
See Figure 5-6 for location
of Meter Board pots .
Set VERNIER com-
pletely cw and adjust
Meter Board pot .
(A) for a +3 dBm
OUTPUT meter reading .
Set front panel
controls as follows :
FREQUENCY
switches to 50 .000 MHz, MODE
to CW, VERNIER completely cw and OUTPUT
dial to +10 dBm .
Calibrate power meter
and its thermistor or power sensor . Set
power meter to the +15 dBm range ; then
connect
thermistor or sensor to RF OUT
connector of Model 3000 .
Adjust
Meter Board pot . (F) for a +13
dBm power meter
reading . Set front
panel VERNIER for -7 dBm reading on OUT-
PUT meter and set power meter to the +5
dBm range .
Adjust Meter Board pot . (E)
for +3 dBm power meter reading . Again
set power meter to the +15 dBm range and
turn front panel VERNIER fully cw. Re-
peat this paragraph until +13 dBm and
+3 dBm power meter readings are obtained
without further adjustment of Meter Board
pots . (E) and (F) .
5-6
Set OUTPUT dial to 0 dBm and power meter
to the +5 dBm range .
With VERNIER com-
pletely cw, adjust Meter Board pot . (C)
for a +3 dBm power meter reading . Turn
VERNIER for -6 dBm reading on OUTPUT
meter and set power meter to the -5 dBm
range .
Adjust Meter Board pot . (D) for
-6 dBm power meter reading . Repeat this
paragraph until +3 dBm and -6 dBm power
meter readings are obtained without fur-
ther adjustment of Meter Board pots . (C)
and (D) .
Set Model 3000 front panel controls as
follows :
FREQUENCY switches to 520 .000
MHz, MODE to AM, FREQ to VERNIER, AM/FM
Vernier control to OI AM and OUTPUT dial
to 0 dBm . Set power meter to the 0 dBm
range and adjust
front panel VERNIER
for a -3 dBm reading on
power meter .
Set power meter to the +5 dBm range and
adjust AM/FM Vernier to 1001 AM .
Adjust
Meter Board pot . (G) for +3 dBm reading
on power meter .
5 .3 .11 Final Frequency Check - M30
Connect frequency counter to signal gen-
erator and set front panel controls as
specified in Section 5 .3 .4 . Note fre-
quency reading on counter ; if it does
not agree with the selected FREQUENCY
within
accuracy specifications, very
carefully adjust M30 FREQUENCY ADJUST
trimmer (See Figure 5-5) until desired
frequency is obtained .
5 .3 .12 FM Reference Adjustment - M29-1
See Figure 5-6 for location of M29-1 ad-
justments .
Connect frequency counter to
front panel RF OUT connector ; then set
other front panel controls as follows :
FREQUENCY to 40 .000 MHz, MODE to
CW,
FREQ to VERNIER, AM/FM Vernier at mini-
mum,
VERNIER fully cw and OUTPUT dial
at +10 dBm . Record the CW frequency
shown on frequency counter .
1(P/ V
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