Check Oscilloscope Adjustment; Check Individual Components - Tektronix 11A52 Service Manual

Maintenance
( 5. Check Oscilloscope Adjustment
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Check the electrical adjustment of the 11A52, or of the affected circuit if the trouble appears in one circuit. If
the apparent trouble cannot be isolated to a defective component, the trouble may only be a result of
maladjustment. Complete adjustment instructions are given in Section 2, Checks and Adjustment, in the Service
Reference Manual.
6. Check Individual Components
The following procedures describe methods of checking individual components in the 11A52. Components that
are soldered in place (excluding integrated circuits) are best checked by first disconnecting one end. This
isolated the measurement from the effects of surrounding circuitry.
CAUTION
To avoid electric-shock hazard, always set the oscilloscope ON/STANDBY switch to ST AND BY
before removing or replacing components.
If the green light indicator remains lit after the ON/STANDBY switch is moved to ST AND BY, the
power has been internally locked ON. To remove or replace components, use the Principal Power
Switch (rear panel) to shut OFF the power.
Transistors
A good check of transistor operation is actual performance under operating conditions. A transistor can most
effectively be checked by substituting a new component for it (or one which has been previously checked).
However, be sure that circuit conditions are not such that a replacement transistor might also be damaged if
substitute transistors are not available, use a dynamic tester. Static type testers are not recommended, because
they do not check operation under simulated operating conditions.
~ntegrated Circuits
Integrated circuits can be checked with a test oscilloscope, digital tester or by direct substitution.
CAUTION
Direct substitution must not be attempted with soldered-in integrated circuits. The IC, circuit board,
or both, could be damaged due to the heat required to melt the solder from the connections. Refer to
Soldering Techniques earlier in this section. Use care when checking voltages and waveforms around
the integrated circuits so that adjacent leads are not shorted together. The integrated circuit test
clip provides a convenient means of clipping a test probe to the in-line, multi-pin integrated circuits.
A good understanding of the circuit operation is essential to troubleshooting circuits using integrated circuits.
Operating conditions and other information for the integrated circuits are given in Section 2, Theory of
Operation and Section 6, Schematic Diagrams and Circuit Board Illustrations.
11A52 Extended Service Manual 3-23