Audio Troubleshooting; Audio Troubleshooting Test Instructions - Nokia RM-701 Service Manual

RM-701
BB Troubleshooting and Manual Tuning Guide
Figure 12 Proximity sensor test

Audio troubleshooting

Audio troubleshooting test instructions

Single-ended external earpiece and differential internal earpiece outputs can be measured either with a
single-ended or a differential probe.
When measuring with a single-ended probe each output is measured against the ground.
Internal handsfree output is measured using a current probe, if a special low-pass filter designed for
measuring a digital amplifier is not available. Note also that when using a current probe, the input signal
frequency must be set to 2 kHz.
The input signal for each loop test can be either single-ended or differential. Exception to this is a digital
microphone which needs input signal from an external sound source (laptop speaker) to playback, eg. 1 kHz
sine wave from 5 cm distance.
Required equipment
The following equipment is needed for the tests:
• Oscilloscope
• Function generator (sine waveform)
• Current probe (Internal handsfree DPMA output measurement)
• Phoenix service software
• Battery voltage 3.7V
• Sound source (laptop speaker or B&K type 4231 calibrator)
Test procedure
Audio can be tested using the Phoenix audio routings option. Three different audio loop paths can be
activated:
• External headset mic to earpiece
• External headset mic to IHF mono
• Internal digital microphone to headset
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