Audio troubleshooting
Audio troubleshooting test instructions
Differential external earpiece and 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.
The input signal for each loop test is single-ended.
Required equipment
The following equipment is needed for the tests:
• Oscilloscope
• Function generator (sine waveform)
• 'Active speaker' or 'speaker and power amplifier'
• Phoenix service software
• Battery voltage 3.7V
Test procedure
Audio 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
• External microphone to External earpiece
Each audio loop sets routing from the specified input to the specified output enabling a quick in-out test.
Loop path gains are fixed and they cannot be changed using Phoenix. Correct pins and signals for each test
are presented in the following table.
Phoenix audio loop tests and test results
The 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 accessory
during measurement causes a significant drop in measured quantities.
Loop test
Input
terminal
Output
terminal
Path
gain [dB]
(fixed)
Input
voltage
[mVp-p]
Differential
output
voltage
[mVp-p]
Output
DC level
[V]
Output
current
[mA]
External Mic to
External
Earpiece
XMICP and
GND
HS_Ear_L
and GND
0.8
1000
1100mV
0.5
N/A
External Mic to
Internal
Earpiece
XMICP and
GND
EarP and
GND
-0.5
1000
940mV
1.2
N/A
EarN and
GND
RM-257; RM-270; RM-277
BB Troubleshooting and Manual Tuning Guide
Issue 1
COMPANY CONFIDENTIAL
Page 3 –37
Copyright © 2007 Nokia. All rights reserved.
