General Instructions For Gsm1800/1900 Tx Troubleshooting; Dcs 1800/Pcs 1900 Tx Fault Finding Flow Chart - Nokia NEM-4 Series Troubleshooting Instructions

CCS Technical Documentation
• The power amplifier is getting a correct VBATRF supply via L805 & L809.
• Mjoelner's supply voltages VR1A, VR2, VR3, VR4, VR5 & VR7 are all working cor-
rectly.
Is Signal at
NO
Change
TX_GSM on
L801
L801 OK?
YES
Is Signal at
Antenna pin
NO
of Z601 ok?
YES
Change X602
RF Connector
Check Antenna
Switch Control
YES
Lines. Do they
match the results
in the table?
NO
Change Check L701,
Antenna L702 & L703.
Switch OK?
NO
Replace
Inductors

General instructions for GSM1800/1900 TX Troubleshooting

Apply an RF-cable to the RF-connector to allow the transmitted signal to act as normal.
RF-cable should be connected to measurement equipment (GSM Test equipment, Power-
meter, Spectrum Analyzer, or similar).

DCS 1800/PCS 1900 Tx fault finding flow chart

The following diagram assumes the following:
• Phoenix has been set up as shown previously (selecting DCS 1800 in the RF con-
trol box).
• Relevant components have been visually inspected for orientation, placement
etc.
• The Transmit Signal has been checked with a Spectrum Analyzer at the RF con-
nector, X602 and was found to be low or non-existent.
• The VCO is running correctly.
• The Power Amplifier is getting a correct VBATRF supply via L805 & L809.
• Mjoelner's supply voltages VR1A, VR2, VR3, VR4, VR5 & VR7 are all working cor-
rectly.
Issue 1 09/2003
Company Confidential
START
Is Signal
Is EGSM
YES YES
at C834
TXIN signal
OK?
at R805 OK?
NO
Probe VPD_900Signal
on R818 and set Power
Level to 19 using Phoenix.
Is Pulse Pk-Pk 2.8V?
NO
YES
Replace PA
Check / Replace
R805, C820, C821
YES
R 806
KEY
Test using
Spectrum Analyzer
Copyright  2003 Nokia Corporation.
Company Confidential
NO
Is Signal at
C733 OK?
R
YES
R 806
Is signal at
L807 OK?
YES
Is Signal at V802
YES
Collector OK?
NO
Is VTXB
_900 OK?
NO
YES
Test using Check /
Oscilloscope Inspect
RF Troubleshooting
NO
Are TX I & Q on
C715 & C716. OK?
YES
Change UEM?
Are digital I & Q
signals OK on
Are TXP &
TXC visible? J123 & J214?
YES NO NO
TXP TXC
NO
Is VR2
2.8V on
C731?
NO YES
Check Z701 & Change
Biasing components Mjoelner
Check V802 &
associated components
End
Action
Page 6(b)-83
NEM-4
NO
OK?
YES
NO
Change
UPP
Change
UEM