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Section V
Paragraphs 5-30 to 5-37
5-33.
MAINTENANCE
OF
OPTIONS
01
AND
02.
5-34.
Operating
instructions
for Model 415E instru-
ments with Option 01 (internally installed battery) and/
or Option 02 (rear panelinput connector) is found in
section
Ш.
Paragraphs
1-6 explain what is covered
by
these
two
options.
Installation
and
removal
instructions
are
given in the appendix at the rear of
this manual.
5-35.
TROUBLESHOOTING.
5-36.
LOCATING TROUBLE,
5-37.
Always
start locating trouble
with a thorough
visual inspection for burned-out or loose components,
loose
connections,
or any conditions which suggest a
source of trouble.
Check the fuse to see that it is not
open.
5-38.
If trouble cannot be isolated to a bad component
by visual inspection, the trouble should be isolated to
а circuit section.
Isolation to a circuit section can be
accomplished
by using the waveforms
(Figures
5-5
through
5-8) and using the front panel performance
tests (Table 5-2).
$-39.
POWER SUPPLY TROUBLE.
5-40. Correct operation of the power supply is vital
to proper operation of the SWR Meter. Noise or vari-
ation in the regulated voltages causes erratic instru-
Model 415E
ment operation. Noiseor variationinthe offset current
Supply causes erratic operation when the 415E isused
for expanded
operation
(i.e., EXPAND
control set to
any position
other
than NORM).
Refer to Paragraph
4-25
for
a discussion
of power
supply operation.
9-41. COMPONENT
TROUBLE ISOLATION.
5-42. The following procedures and data are given to
aid in determining whether atransistor is operational.
Tests
are given for both in-circuit and out-of-circuit
transistors and should be useful іп determining whether
a particular section trouble is due to a faulty transistor
or an associated component.
5-43.
IN-CIRCUIT
TESTING,
5-44.
The
common
causes
of transistor failures are
internal
short-
and open-circuits.
In transistor cir-
cuit testing the most
important
consideration
is the
transistor
base
- emitter
junction.
Like the control
grid of a vacuum tube, this is the operational control
point in the transistor.
This junction is essentially a
solid-state
diode.
For the transistor to conduct, the
diode must conduct; that is, the diode must ре forward
biased.
As with simple diodes, the forward-bias po-
larity is determined by the materials forming the junc-
415Е-А-21
Figure 5-ЗА.
Switch Component Location
5-10
4ISE-A-22
Figure 5-3B.
Switch Component Location
02152.2
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