Wavetek 3000 - Phase-Locked Loop #1 Adjustment M31 A; Phase-Locked Loop #2 Adjustment M32 A; Phase-Locked Loop #3 Adjustment; Phase-Locked Loop #4 Adjustment

MAINTENANCE
Adj us t M30
FREQUENCY
ADJUST trimmer (Fig-
ure 5-5) for minimum frequency indication
on counter ; then, carefully turn FRE-
QUENCYADJUST trimmer clockwiseuntil
counterindicates the frequency select-
ed by FREQUENCY switches . Disconnect
counter from RF OUT connector . A final
frequency check will be covered in
paragraph 5.3 .11 .
5
.3.5 PHASE-LOCKED LOOP #1 ADJUSTMENT
M31A
No adjustment of module
M31A is necessary .
5
.3.6 PHASE-LOCKED LOOP
#2 ADJUSTMENT
M32A
See
Figure 5-5 for location of
M32A test
points and Figure
5-6 for adjustment
controls . Set
frequency to 200 .000 MHz
and
other front-panel controls
as in
Section 5 .3 .4 .

Connect
digital volt
meter to M32A pin
14,
and

carefully ad-
just

both

M30 -1 trimmers

(A
and
B) to
producea minimum
reading on voltmeter .
This
voltageshouldbe between
+0 .5
V
and+3 .0 VDC . Set
frequency to . 239 .000
MHz,and note that
voltmeterreading is
still
within above limits .
Set frequency to
200 .000 MHz and con-
nect scope
vertical input (DC, 1 V/cm)
to
M32A pin 15 . Adjust M32A control (A)
for a 0 V scope
indication . Set Fre-
queney to
239 .000 MHz, and
adjust M32A
control (B)
to againproducea 0 V scope
indication .
5.3 .7 Phase-LockedLoop #3 Adjustment
P .L .L . #3 consists of two modules : The
M33 and the
M9
W . The
test point is on
moduleM33 (Figure 5-5), while the ad-
justment controls are on module M9W
(Figure 5-6) .

Set
FREQUENCY
to 250 MHz,
and

other
front
panel controls as in
Section 5 .3.4 .

Connect scope vertical
input (DC,

1 V/cm) to M33 pin 5 .

Adjust
M9W control (D) for a 0 V
scope
indica-
tion .
Set front-panel controls as follows :
MODE
to
FMx100, FREQ
to
1
kHz and
AM/FM
Vernier at maximum . Set scope vertical
input (on M33 pin 5)
for AC,
50
mV/cm .
Adjust
M9W
control (C) for minimum (null)
indication of 1 kHz
sine wave on scope .
Set
FREQ
to 400 Hz and note that scope
presentation is a 400 Hz sine wave .
5 .3 .8 Phase-LockedLoop #4 Adjustment
Calibration of P.L .L .
#4 involves three
modules : M172, M9W and
the M34 . Test
points are located on modules- M2Mand
M34 (Figure 5-5), while adjustment con-
trols are located
on modulesM172and
M9W
(Figures 5-4 and 5-6) .
Set FREQUENCY switches for 250 .000 MHz
and other front panel controls as in
Section 5 .3.4 .

Connectdigital volt
meter to M172 pin
°) . ;

then,

adj
ust
M172
250 MHz control (Figure 5-4) for a 0 .00
V reading on voltmeter .

The voltmeter
maynowbe disconnected .
Connectfrequencycounter to RF OUT con-
nector and connect scope vertical input
(DC, 1 V/cm) to M34 pin 8 .

Adjust M9W
control (A) for 0 V on scope .

The count-
er
should indicate a frequency of 250
MHz .

NOTE :

Due to the way the M34 locks
on
harmonics of 40 MHz, it is possible
to adjust M9W control
(A) for "0 V" at
multiples of 40 MHz offset
from 250 MHz .
If this happens, it
will be necessary to
readjust M9W control
(A) several turns
to
break lock and relock
at the next
multiple of 40 MHz until "0
V" can be
obtained with a 250 MHz counter
reading .