Figure 10 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
RM-750
BB Troubleshooting and Manual Tuning Guide
Page 3 – 26 COMPANY CONFIDENTIAL Issue 1
Copyright © 2011 Nokia. All rights reserved.
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