Nokia RM-57 Service Manual
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Contents
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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 measuringa digital amplifier is not available. Note also that when using a current probe, the input signal frequency mustbe set to 2kHz.The input signal for each loop test can be either single-ended or differential.Required equipmentThe following equipment is needed for the tests:• Oscilloscope• Function generator (sine waveform)• Current probe (Internal handsfree DPMA output measurement)• Phoenix service software• Battery voltage 3.7VTest procedureAudio can be tested using the Phoenix audio routings option. Three different audio loop paths can be activated:• External microphone to Internal earpiece• External microphone to Internal handsfree speaker• Internal microphone to External earpieceEach audio loop sets routing from the specified input to the specified output enabling a quick in-out test. Looppath gains are fixed and they cannot be changed using Phoenix. Correct pins and signals for each test arepresented in the following table.Phoenix audio loop tests and test resultsThe results presented in the table apply when no accessory is connected and battery voltage is set to 3.7V.Earpiece, internal microphone and speaker are in place during measurement. Applying a headset accessoryduring measurement causes a significant drop in measured quantities.The gain values presented in the table apply for a differential output vs. single-ended/differential input.Loop test Input terminal OutputterminalPathgain [dB](fixed)Inputvoltage[mVp-p]Differentialoutputvoltage[mVp-p]Output DClevel[V]Outputcurrent[mA]External Mic to ExternalEarpieceXMICP and GND HSEAR R P,HSEAR R Nand GND-2.9 1000 720 1.2 NAHSEAR P,HSEAR N andGNDXMICN and GND HSEAR R P,HSEAR R Nand GNDHSEAR P,HSEAR N andGNDRM-57/58BB Troubleshooting and Manual Tuning Guide Nokia Customer CareIssue 1 Company Confidential Page 6–49Copyright ©2005 Nokia. All Rights Reserved. |
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