Wavetek 3000 - Phase-Locked Loop Troubleshooting

andDC
voltages are correct,
module M31A
is defective .
Phase-LockedLoop #2 -
Unlocking of loop
#2 can be causedby
defectivemodules
M172, M30, M32 or RF
cables connecting
M30 to M32 .
Connect digital
voltmeter to M32 pin
11
and observe
voltmeterreading
while
stepping
through frequency
range from
200 to 239
MHz in 1 MHz
steps .

The
voltmeter
reading should
change-0 .2 V
per MHz
from 0 V at 200
MHz to -7 .8 V at
239 MHz .

Thesevoltages
indicateproper
operation
of moduleM172 .
ModuleM30 can be
checkedby measuring
the 1 MHz and 1440
MHz signals
directly
at the M30 . The
levels specified
in
Table 5-2 indicate
proper operation
of
module M30 .

If
the M30 outputs
are cor-
rect, the
trouble lies in
module M32 or
the RF cables .
Phase-Locked
Loop #3 - Unlocking
of this
loop in CW
mode canbe
caused by de-
fective
modules M9W, M30,
M33 or con-
nectingRF
cables . In
addition, unlock-
ing in FM
modes can be
caused by a de-
fective
moduleM29-1 .
TheM9W
can be checked
by

measuring
the 1198 MHz narrow
oscillator
signal
directly at
module M9W . The
level spe-
cified in Table
5-2 indicates
proper
operation of the
M9W .
Measure the
1200 MHz (120 comb)
and 2
MHz signals
directly at module
M30 . Pro-
peroperation
of the M30 is
indicated by
the signal
levels specified
in Table 5-2 .
Set
MODE switch to
FMxl, FREQ at
VERNIER
and AM/FM
Vernierat maximum .
Measure
1 .5 to 2.5 MHz
signal (exact
frequency
is dependent
uponsetting of
AM/FM Ver-
nier) directly
at moduleM29-1 .
If
signal
level is as
specified in Table
5-7 .
s
properoperation of
module M29-1
is
indi-
cated .
MAINTENANCE
If
input
signals
to module M33 from mod-
ules
M9W, M30 and M29-1 are correct, the
trouble is in module M33 or
its connect-
ing RF
cables .
Phase-Locked
Loop #4 - Unlocking of loop
#4
may,
under certain
conditions,
be
caused by problems originatingin the
otherloops . Therefore, loops#l, 2
:and
3 should be operatingproperlybefore
troubleshooting loop #4 .
Unlocking of

loop
#4
can
be

caused by
defective
modules M172, M9W,
M30, M31,
M32, M34 or
connectingRF cables .
Connect
digitalvoltmeter to M172 pin 1 .
The
voltmeter reading should be 0 .00 V
withFREQUENCY switches set at
000
MHz,
-2 .5 V at 250 MHzand -5 .0 V at
500 MHz .
These voltages indicate proper operation
of
module
M22 .

Connectvoltmeter
to M2M
pin 8 .

The voltmeter
reading shouldbe
+6 to +7 V at
000 MHz, 0 V at 250 MHz
and-8 V at 500 MHz . If
these voltages
are obtained, module
M172 is operating
properly .
Measure the Wide
Oscillator signal at
moduleM9W .
The frequencywillbe be-
tween
1198 MHz and 1718 MHz, depending
upon
the setting of the FREQUENCY
switch
es .

If
the signallevel is as specified
in Table 5-2, module M9W is operating
correctly .
Measure the 40 comb line at
moduleM30 .
The 40 MHz harmonics
from 40 MHz to 280
MHz should be
fairly equal in amplitude
and the levelshould
be as specified in
Table 5-2 . This
level indicates proper
operation of
the M30 module .
Measure
the 1448 MHz to 1487 MHz signal
at moduleM32 . The exact
frequency is
dependent upon the
setting of the MHz
FREQUENCY switches . If
the level is as
specified in
Table 5-2, the M32 is op-
erating properly .
Last, measure
the 10 MHz to 9 .001 MHz
output of
the M31 module .

The output
5-9