Nokia 6600 - Fault-Finding Chart: TX-BB Interface and Control Signals

NHL-10
CCS Technical Documentation RF Troubleshooting
28 COMPANY CONFIDENTIAL ISSUE 2 01/2004
Copyright © 2003 Nokia. All Rights Reserved.
Fault-finding chart: TX-BB interface and control signals
Figure 3: Fault finding chart of BB-TX interface & some control signals
Figure 4: Oscilloscope screen shots
Start
Not OK
Check UEME
(D190) in BB area
Not OK
Check UEME
(D190) in BB area
OK
OK
Not OK
Check UPP
(D100) in BB area
OK
Not OK
Check serial
interface between
Mjolner & UPP
OK
Use Phoenix to set TX_Data_Type to 'Random'
and to set TX Power Level to '5'
Use the oscilloscope to check the voltage supply line to
the transistorized pre-amplifier: VTXB_900
Not OK
Using the oscilloscope, check TXP from UPP:
Line
Testpoint Vpp Frequency
TXP J610 1.8V 217Hz
Using the oscilloscope, check TXC and TX IQ lines from UEME to Mjolner:
Line
Testpoint DC Voltage AC Voltage Frequency
TXIOUTP R715 1.1Vdc 0.4Vp-p 67kHz
TXIOUTN R715 1.1Vdc 0.4Vp-p 67kHz
TXQOUTP R716 1.1Vdc 0.4Vp-p 67kHz
TXQOUTN R716 1.1Vdc 0.4Vp-p 67kHz
TXC J611 Depends on the power level 217Hz
Using a multimeter, check power supply lines to Mjolner:
Line
Voltage Test Points
VR1a 4.75V J612
VR2 2.78V J613
VR3 2.78V J614 (J601)
VR5 2.78V J616
VR6 2.78V J617
VR7 2.78V J618
VR1A
VR3
VR6
VR5
VR7
TXP
TXIOUTP
TXIOUTN
TXQOUTN
TXQOUTP
TXC
VR2
Mjolner output
bias network
Cont1Cont2Cont3
Using the oscilloscope, check control signals from Mjolner to ASM
1
:
Line
Testpoint GSM900 GSM1800 GSM1900 Period
Cont1 R702 0V 2.7V 2.7V 4.615ms
Cont2 R703 0V 2.7V 2.7V 4.615ms
Cont3 R701 2.7V 0V 0V 4.615ms
1
ASM
=
Antenna
Switch Module
Check serial
interface between
Mjolner & UPP
Ctrl signals to ASM:
( DCS/PCS )
Cont1
Cont2
2.7V
4.615ms
4.
TXP-signal
4.615ms
TXC-signal
EGSM900
channel = 37
PL = 5
6
VTXB_900
2.7V
4.615ms
0.5Vpp
1.1Vdc
~67kHz
waveform for all 1's
Typical oscilloscope plots
of the four TXIQ-lines:
zoom