Daniels VT-3/140-SWA2, Instruction Manual

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Audio Processor Board Instruction Manual 5-1
5 TROUBLESHOOTING - TEST EQUIPMENT NEEDED
1 Variable Power supply/supplies to supply 9.6V and 8.0V at the same time.
2 Digital Voltmeter to measure RMS AC Volts, DC Volts, DC Current and resistance.
3 20 MHz Oscilloscope, single channel.
4 Audio Signal Generator (600 Ohm Output Impedance) capable of frrequencies from
67 Hz to 5000 Hz.
Power Supply
•
Connect a regulated power supply with +9.5V as follows:
Positive to P2-4
Negative to P1-4 (Ground)
•
Connect a regulated power supply with +8.0V as follows:
Positive to P2-3
Negative to P1-4 (Ground)
•
Measure total current from both power line inputs:
Table 7 Operating Current
Voltage Input Current (mA)
8.0V 15.7
9.5V 0.47
5.1 Balanced Input Test
Connect an Audio Generator set for a 2.4 kHz tone @ 0 dBm (775 mV RMS) output to the
Balanced Input (P1-1 and P1-2). Refer to Table 8
Waveform Levels for measurement points,
levels and waveforms that should be present.
Change Audio Generator settings for a 1 kHz tone @ -8 dBm (309 mV RMS) output. Refer to
Table 8
Waveform Levels for levels and waveforms that should be present.
5.2 Frequency Response Test
Reduce Audio Generator level to –18 dBm (98 mV RMS). Step frequency to 500, 1000, 2000 and
3000 Hz. Ensure that the results conform to the 6dB//- 1 dB from 300 Hz to 2500 Hz
referenced to 1000 Hz. Measurements are made at JU8 with respect to ground.