User Guide

PAMS Technical Documentation Troubleshooting Instructions

NSB-5

Issue 1 03/01 Nokia Mobile Phones Ltd. Page 21

Audio failure: Uplink (microphone) is broken

Figure 15: Fault Finding for Broken Uplink Audio with Working Downlink

Uplink is broken

Voltage at E101 is 1.8V

Voltage at E100 is 0.3V

during call

Check:

microphone connections (through slide)

micbias components (V111, R148, R116,

R119, V100)

Micbias control line (one side of R149)

during call

Voltage on COBBA side of

C117 & C121 is 1.4V during call

Check N200 COBBA

Yes

Audio voltage (few

millivolts) on COBBA side of

C117 & C121 during call

Check C117, C121 and

PCB

Check N200

Yes