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Adjustment Procedures
AM700 Audio Measurement Set Service Manual
5–5
Power Supply Verification
The power supply adjustment is not accessible when the supply is installed in the
AM700. The power supply is adjusted either using a load unit (in manufacturing)
or during servicing using the correct extender cables. It is not a normal customer
adjustment. Under normal conditions, the power supply should not require
adjustment. The verification procedure determines if there is a problem with the
power supply that requires servicing.
The following test equipment is needed to verify and adjust the power supply:
H Test oscilloscope with 1X probe
H Digital voltmeter
1. Turn on the AM700 and wait for the initialization to finish.
2. Use an oscilloscope with a 1X probe to check the power supply voltages and
ripple as shown in Table 5–3.
a. Input Coupling AC
Trigger Auto
Volts/Div 50 mV
Table 5–3: Power supply voltages and ripple tolerances
Voltage Tolerance Range Max Load Ripple (mV) Noise (mV)
+5 V 0 to +2% 5.0 to 5.1 V 20 A 50 100
+15 V 2% 14.70 to 15.3 V 3 A 20 100
–15 V 2% –15.3 to 14.7 V 2 A 20 100
–16.5 V 5% –17.33 to –15.68 V 2 A 50 100
b. Check the +5 V on the main CPU board at J33 pin 1. Pin 2 is ground.
c. Check the +15 V on the main CPU board at J33 pin 3. Pin 4 is ground.
d. Check the –15 V on the main CPU board at J33 pin 5. Pin 4 is ground.
The –16.5 V source is not accessible with the instrument assembled.
If any of the supplies are out of tolerance, the power supply may have a problem
and should be replaced. See the Remove and Replacement Procedures in the
Maintenance section to remove the power supply from the AM700. You can also
contact your nearest Tektronix representative to arrange for your AM700 to be
returned to Tektronix Factory Service for repair.
Test Equipment Required
Verification Procedure