Nokia rx-34 Service Manual

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Nokia rx-34 Service Manual Manual pdf 145 page image

Audio troubleshootingAudio troubleshooting test instructionsHeadphone outputs are single-ended type thus those must be measured against ground.Internal loudspeakers outputs are measured using a current probe, if a special low-pass filter designed formeasuring digital amplifiers is not available.Required equipmentThe following equipment is needed for the tests:• Oscilloscope• Current probe (Internal handsfree DPMA output measurement)• Low-pass filter designed for DPMA measurements• Phoenix service software• Battery voltage 3.7V• Nokia HS-48 headset• Sine signal generator• MultimeterTest procedureAudios can be tested using the Phoenix audio routing options. Two different audio loop paths can beactivated:• From internal microphone to headphone output (HP microphone in Ext earpiece out)• From external microphone to headphone output (Ext microphone in Ext earpiece out)These loops are basically meant for device’s internal microphone and headset’s microphone testing.For internal loudspeakers and headphone output testing there is possibility to use test signals generatedinside of the device.Note: Sine test signals frequency and amplitude are fixed.It’s possible to route the signal to the following outputs:• Headphone left channel (Generated earpiece left out)• Headphone right channel (Generated earpiece right out)• Internal loudspeaker (Generated int handsfree out)Each audio output configuration sets the internal test signal generator or microphone routing to the specifiedoutput. Test signal path gains are fixed and they cannot be changed using Phoenix. Microphone is tested bytalking to the microphone and listening the output signal using headphones/headsets.Correct measurement/test points for each test case are presented in a table below.Phoenix audio loop tests and test resultsThe results presented in a table apply when no accessory is connected and the battery voltage is set to 3.7V.Internal loudspeakers are in place during the measurements. Applying a headset or a headphone duringmeasurement causes a significant drop in measured quantities.Output device Output terminals Output voltage (mVrms)Headphone left X4120 pin 5 and gnd ~43mVrmsRX-34BB Troubleshooting and Manual Tuning GuideIssue 2 COMPANY CONFIDENTIAL Page 6 –37Copyright © 2007 Nokia. All rights reserved.