c. Do you know the stages in your receiver and the job that each stage does?
d. Can you follow a schematic diagram reasonably well?
e. Are you familiar with the test equipment you'll be using? Do you know the
purpose of each piece of test equipment?
5-3.
GENERAL PROCEDURE FOR TROUBLESHOOTING
Unfortunately, there is no one set step-by-step procedure for you to follow
which is good for all receivers you'll work on. Too many differences exist within
the receivers themselves.
However, you can develop an overall method of
troubleshooting which will help you get started and avoid the old "try this, try
that" technique.
Once you've developed a method, you'll attack each set in the
same way. First of all, you should always have the technical manual (TM) for the
specific piece of equipment.
In addition to giving you all of the schematic
diagrams
you'll
need,
the
TM
provides
the
step-by-step
procedure
for
troubleshooting the specific set you're working on.
Refer to the section on
troubleshooting.
Every equipment TM has a section about troubleshooting.
The
whole idea of troubleshooting is to isolate the trouble to a specific defective
component in the receiver. Naturally, you'll have to localize trouble to the bad
stage first. Then you can find the bad component by making voltage and resistance
checks within the stage.
a. Visual Inspection.
There is an old saying that goes like this: "What you
don't see can't hurt you." It might be true in some cases, but not in
troubleshooting.
What you don't see can hurt you, so the moral is: As the first
step in troubleshooting, take a good look at your set.
(1) A good visual inspection helps accomplish three things.
(a) It shows you how the chassis is laid out in regard to stage and
component location. Use the pictorials provided in the TM, showing the
top and bottom view of the chassis.
This will help you to identify
most of the components and stages.
(b) It may help you locate the bad component.
(c) It helps you avoid future troubles by finding and correcting frayed
wires, poor mechanical connections, and loosely mounted components.
(2) While making your visual inspection, clean the set with a fine-bristled
brush. Dirt is a real troublemaker, particularly on sets that are getting
rugged field use.
Dirt can be a source of present trouble, and it can
also be a source of future trouble.
(3) Look closely for burned or blistered resistors or for bulging electrolytic
capacitors.
Faulty choke coils and transformers may also be found by
looking for melted wax, varnish, or sealing compound around the windings.
Any sign of melted insulation of this type is usually the result of
overheating caused by a shorted winding.
(4) Perhaps some of the biggest troublemakers you'll come up against will be
defective cables, connectors, cordage, and sockets. Field
322 L5
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