Audio Failure - Nokia NSE-6 SERIES Service Manual

NSE–6
Disassembly & Troubleshooting Instructions

Audio failure

Uplink (microphone) and downlink
(earphone) are disfunctional
Voltage at HOOKDET (C260)
2.8 V (without headset)
Voltage at HEADDET (C261)
2.8 V (without headset)
Frequency at J257 is square
wave 8 kHz 2.8 Vpp
Uplink (microphone) is
disfunctional
YES
Voltages at J261 and J262 are
1.8 V and 0.3 V during call
YES
DC voltage at C262 and C263
(on Cobba side) are 1.4 V
during a call
YES
Analog audio signal (few mV) at
C262 and C263 (on Cobba side)
during a call
YES
Check Cobba (N250)
Page 20
YES
NO
Check R259, R260
YES
NO
Check R256, R257, R261
YES
NO
NO
Change slide
NO
Check Cobba (N250)
NO
Check C262, C263 and PCB
routings
Downlink (earphone) is
disfunctional
DC voltage at C291 and C292
are 1.4 V during a call
Analog audio signal (some ten mV)
at C291 and C292 during a call
Technical Documentation
Check Cobba (N250)
NOT OK
Check slide connector, V701, V250..
If OK, check that micbias line
(R267 upper side) is "1" during call
YES
NO
YES
NO
PAMS
Check Cobba (N250)
Check Cobba (N250)
and MAD2 (D200)
Original 08/98