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Maintenance
CAUTION
Excessive heat can cause the etched circuit wiring to separate from the board base material.
Troubleshooting
The following information is provided to facilitate troubleshooting the 11A52 Two Channel Amplifier.
Information contained in other sections of this manual should be used with the following data to aid in locating
a defective component. An understanding of the circuit operation is helpful in locating troubles. See Section 2,
Theory of Operation, for this information.
Troubleshooting Aids
Diagrams
Complete schematic diagrams are given on the pullout pages in Section 6, Schematic Diagrams and Circuit
Board Illustrations. The circuit number and electrical value of each component in the 11A52 are shown on these
diagrams. (See the first page of the Schematic Diagrams and Circuit Board Illustrations section for definitions
of the reference designators and symbols used to identify components in the 11A52.)
Circuit Board Illustrations
An illustration of the plug-in unit showing circuit board placement is provided on the first page of Section 6-
Schema tic Diagrams and Circuit Board Illustrations.
A circuit board component illustration is shown adjacent to the first schematic diagram associated with a
specific circuit board.
Each schematic diagram in Section 6 has a grid matrix with an index to help locate components contained in
that schematic diagram.
Component Color Coding
This amplifier contains composition resistors and metal-film resistors. The resistance values of composition
resistors and metal-film resistors are color coded on the components, using the EIA color code (some metal-film
resistors may have the value printed on the body). The color code is read starting with the stripe nearest the
end of the resistor. Composition resistors have four stripes, which consist of two significant figures, a
multiplier, and a tolerance value (see Fig. 3-7).
Metal-film resistors have five stripes consisting of three significant figures, a multiplier, and a tolerance
value.
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The values of common disc capacitors and small electrolytics are marked on the side of the component body.
11A52 Extended Service Manual
3-17
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Table of Contents
Troubleshooting
