If a small rubber mallet or some insulated
nonmetallic instrument is used to tap tubes
Test equipment
Manual or stock number
or individual components, be careful not to
disrupt the position of the part being tapped Electronic Multimeter TS-505/U ------ TM 11-5511
--
Multimeter TS-352/U--------------------- TM 11-5527
-
and other parts within the signal generator.
Electron Tube Test Set TV-2/U------- TM 11-2661
--
Frequency Meter TS-174B/U---------- TM 11-5044
-
54. Troubleshooting Data
Always check the circuit label, since the schematic Frequency Meter TS-175B/U---------- TM 11-5050
-
diagram in the manual may not include circuit changes Panoramic Indicator IP-173/U--------- TM 11-5086
-
made during equipment production. Take advantage of Frequency Meter FR-67/U-------------- TM 11-2698
-
the material supplied in this manual. It will help in the Signal Generator TS-497A/URR ----- TM 11-5030A
--
rapid location of faults. Consult the following trouble- Radio Receiver R-274/FRR------------ TM 11-897
-
Signal Generator SG-71/FCC--------- TM 11-5088
-
shooting
Barretter bridge---------------------------- Measurements
-
Model 202B
Fig.
Spectrum Analyzer TS-723/U --------- 3F 1722-5.4
--
No.
Title
Fixed attenuator--------------------------- S/N 2 Z 394.85
-
4
Signal Generator SG-3/U, tube location.
Variac CN-16 ------------------------------- S/N 2 Z 9944-16
-
19
Signal Generator SG-3/U, top view interior.
Tuning wand------------------------------- S/N 6 R 38490
-
-
20
Signal Generator SG-3/U, bottom view interior.
21
Rf assembly, left side view.
56. General Precautions
22
Rf assembly, top view.
a. When the unit has been operating r some time,
of
23
Mounting plate for tuning capacitor.
the electron tubes are hot enough to cause a serious burn
24
Typical tuning capacitor assembly.
if they are not handled properly. When removing tubes
25
Rf assembly, bottom view.
for test or replacement, use an appropriate tube puller or
33
Filter assembly, interior view.
Audio oscillator and deviation indicator assembly, dry cloth to protect the fingers.
34
b. When probing inside the signal generator, be
bottom view.
Audio oscillator and deviation indicator assembly, careful not to disturb the position of, or damage, any part.
35
c. Careless removal or replacement of parts often
top view.
creates additional faults.
36
Power supply section, bottom view.
d. If it is necessary to remove or replace an
37
Voltage, resistance, and parts location of terminal
assembly or part which is secured mechanically, be sure
boards.
to install all screws, nuts, bolts, fiat washers, lockwashers,
38
Tube-socket voltage and resistance diagram.
spacers, spacer posts, etc., that were removed. Note the
42
Resistor color code.
following points:
43
Capacitor color code.
(1) Before a part is unsoldered, note its exact
44
Signal Generator SG-3/U, schematic diagram.
position.
Install the part in its original
position. If a part has a number of leads
55. Test Equipment Required for Troubleshooting
connected to it, tag each lead for positive
The items of test equipment required for
identification to facilitate and assure correct
troubleshooting Signal Generator AN/URM-70 are listed
installation.
below. Manuals associated with each item also are listed.
(2) Be careful not to twist or kink other leads by
pulling or pushing them out of the way.
37
