Wavetek 3000 Instruction Manual page 79

and DC voltages are correct, module M31A
is defective .
Phase-Locked Loop #2 - Unlocking of loop
#2 can be caused by
defective modules
M172, M30, M32 or RF cables
connecting
M30 to M32 .
Connect digital voltmeter to M32 pin 11
and observe
voltmeter reading
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 .
These voltages indicate proper
operation of module M172 .
Module M30 can be checked by
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
can be caused
by de-
fective modules
M9W, M30, M33
or con-
necting RF cables .
In addition, unlock-
ing in FM modes can be
caused by a de-
fective module M29-1 .
The M9W 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-
per operation 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 Vernier at maximum .
Measure
1 .5 to 2 .5 MHz signal
(exact frequency
is dependent upon setting of AM/FM Ver-
nier) directly at module M29-1 . If signal
level is as
specified in Table
5-7.
s
proper operation 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 originating in the
other loops . Therefore, loops#l, 2 :and
3 should be operating properly before
troubleshooting loop #4 .
Unlocking of
loop #4 can be
caused by
defective
modules M172, M9W, M30, M31,
M32, M34 or connecting RF cables .
Connect digital voltmeter to M172 pin 1 .
The voltmeter
reading should be 0 .00 V
with FREQUENCY switches set at 000 MHz,
-2 .5 V at 250 MHz and -5 .0 V at 500 MHz .
These voltages indicate proper operation
of module M22 .
Connect voltmeter to M2M
pin 8 . The voltmeter reading should be
+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
module M9W .
The frequency will be be-
tween 1198 MHz and 1718 MHz,
depending
upon the setting of the FREQUENCY switch
es . If the signal level is as specified
in Table 5-2, module M9W is operating
correctly .
Measure the 40 comb line at module M30 .
The 40 MHz harmonics from 40 MHz to 280
MHz should be fairly equal in amplitude
and the level should 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 module M32 . 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