Troubleshooting Techniques; Troubleshooting Procedure - Tektronix 067-0599-00 Instruction Manual

Maintenance—067-0599-00
Transistor Tester
Description: Dynamic-type tester.
Purpose: Test semiconductors
Recommended Tektronix types: 576 Curve Tracer,
577/177 Curve Tracer system, 7CT1N Curve tracer unit and
a 7000-series oscilloscope system, or a 5CT1N Curve
Tracer unit and a 5000-series oscilloscope.
Multimeter
Description: Voltmeter, 10,000 MQ input impedance and
a range of 0 to at least 50 V dc; accuracy, within 0.1%.
Ohmmeter, 0 to 20 MQ. Test probes should be insulated to
prevent accidental shorting.
Purpose: Check voltage and resistance.
Test Oscilloscopes
Description: Frequency response, dc to 1 MHz minimum;
deflection factor 1 mV to 5 V/div. A 10X, 10 MQ voltage
probe should be used to reduce circuit loading.
Purpose: Check operating waveforms.
TROUBLESHOOTING TECHNIQUES
The following troubleshooting procedure is arranged to
check the simple trouble possibilities before proceeding with
extensive troubleshooting. The first few checks ensure
proper connection, operation, and adjustment. If the trouble
is not located by these checks, the remaining steps aid in
locating the defective component. When the defective com-
ponent is located, it should be replaced using the replace-
ment procedure given under Corrective Maintenance.
Troubleshooting Procedure
1. Check Control Settings. Incorrect control settings
can indicate a trouble that does not exist. If there is any
question about the correct function or operation of any con-
trol, see Section 2, Operating Instructions.
2. Check Associated Equipment. Before troubleshoot-
ing, check that the equipment used with this instrument is
properly connected and that the interconnecting cables are
not defective. Also, check the power source.
5-4
3. Visual Check. Visually check the portion of the instru-
ment in which the trouble is located. Many troubles can be
located by visible indications such as unsoldered connec-
tions, broken wires, damaged circuit boards, damaged com-
ponents, etc.
4. Isolate Trouble to a Circuit. To isolate trouble to a
circuit, note the trouble symptom. The symptom often iden-
tifies the circuit in which the trouble is located. When trouble
symptoms appear in more than one circuit, check the af-
fected circuits by taking voltage and waveform readings. In-
correct operation of all circuits often indicates trouble in the
power supply. Check first for correct voltages of the individ-
ual supplies. However, a defective component elsewhere in
the instrument can appear as a power-supply trouble and
may also affect the operation of other circuits.
5. Check Voltages and Waveforms. Often the defective
component can be located by checking for the correct volt-
ages and waveforms in the circuit.
6. Check Instrument Adjustment. Check the adjustment
of this instrument, or the affected circuit if the trouble ap-
pears in one circuit. The apparent trouble may be the result
of misadjustment. Complete adjustment instructions are
given in Section 4.
7. Check Individual Components. The following proce-
dures describe methods for checking individual compo-
nents. Two-lead components that are soldered in place are
best checked by first disconnecting one end. This isolates
the measurement from the effects of surrounding circuitry.
CAUTION
To avoid component damage, disconnect the power
source before removing or replacing semiconductors.
TRANSISTORS. The best check of transistor operation
is actual performance under operating conditions. A transis-
tor can be most effectively checked by substituting a new
comonent or one that has been checked previously. How-
ever, be sure that circuit conditions are not such that a re-
placement transistor might also be damaged. If substitute
transistors are not available, use a dynamic tester. Static-
type testers are not recommended, since they do not check
operation under simulated operating conditions.
INTEGRATED CIRCUITS. IC's can be checked with a
voltmeter, test oscilloscope, or by direct substitution. A