Wavetek 3000 - Troubleshooting Guide; Troubleshooting Hints

5 .4 TROUBLESHOOTING
Set MODE to FMxl_ and adjust M29-1
control
(B) to produce an output frequency that
is approximately 100 Hz above the CW
frequency .
Increase AM/FM Vernier
to
maximum and adjust Modulation Board con-
trol (B) to increase frequencycounter
reading by 5 kHz .
Set MODE to FMx100 and AM/FMVernier to
maximum . Adjust M29-1 control (A)_°or a
frequencycounter reading
of 40
.500
MHz
±10 kHz .
Troubleshooting is generally a system-
atic procedure of "divide and conquer" .
A thoroughunderstanding of the block
diagrams
and-circuit description located
in Section 3 of this manualwill enable
the trouble symptom to be localized to
a particular module or
PC
board . Once
this has been accomplished the module
or board can be replaced, or repaired
with the aid of the proper schematic .
In general, it is preferable to replace
the module or PC-board assembly .
The front-panel
ACCURACY
lamps together
with the four internal module "unlock
indicator"lamps aid in troubleshooting
phase-locked loop problems . Onemodule
in each loop contains an indicatorlamp
which lights to indicate when that loop
is unlocked . The lamps indicate only
which loops are unlocked, but not which
module is at fault .
A problem in a power supply may cause
many symptoms pointing to other areas
and should be checked when the symptom
does not clearly indicate a specific
problem . The loss of the -18 V supply,
for example, will cause the
ACCURACY
lamp
to flash ; while
loss of
the
+18 V
supply willextinguish all
lamps .
The
+18, -18 and
+7 .3
V supplies comprise
the DPS2
power supply which forms the
rear panel of the instrument .

Perfor-
mance of these supplies is indicated in
the CALIBRATIONPROCEDURE .
For
troubleshooting purposes, it is per-
missible to operate the Model 3000 with
any of the plug-inmodules or RF cables
removed ; however, the instrument should
be turned off when removing or installing
modules . If substitute modules are
available,
possibly
from another
Model
3000, this provides an easy method
of
verifying
if a suspected module is de-
fective .
RF cables can be disconnectedfrom the
module output connectors ; then a power
meter or spectrum analyzer can be con-
nected directly to the module connector
for powerlevel or frequency measurements .
Fabrication of a short coax adapter
cable, terminated in a mating connector
for the
modules
on
one end and a BNC
connector on the other, will facilitate
connection of test equipment .
Before engaging in a troubleshooting pro-
cedure,be sure front-panel controls are
set in proper
operating
position . Make
a thorough visual inspection of the in-
strument for such obvious defects as
loose or missing screws, broken wires,
defectivemodule-pin sockets, loose RF
cables andburned or broken components .
5 .4 .1
TroubleshootingHints
MAINTENANCE
The following is a list of several typi-
cal symptoms followed by the probable
cause(s) or a troubleshooting
procedure .
It is assumed the instrument has been
properlycalibrated
previously, and that
a
warmupperiodwill precede
trouble-
shooting .
INTERMITTENT OPERATION - Defectivemod-
ule-pin sockets or loose RF cables .
LOWRF OUTPUT (+10 dBm RANGE) -
If
power
is 10 dB lowon this rangebut is cor-
rect on the 0 dBm range, Meter Board
micro switch S1 is probablynotbeing
actuated by attenuator shaft .
LOWORNO RF OUTPUT (ANY RANGE) - Defec-
tive attenuator or RF cables connecting
to input or output of attenuator, defec-
tive meter board, defectivemoduleMIOW
or
M9W .

Checkvoltageonpin 15 of mod
ule MlOW .

Thevoltage should be approx-
5-7