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Nokia Customer Care
900 Tx troubleshooting flowchart
THE FIRST FLOW DIAGRAM ASSUMES THE FOLLOWING:
•
Phoenix has been set up as shown in the following screen (the Tx
power level may be increased using Phoenix if it makes the Tx pulse
easier to see).
•
Relevant components have been visually inspected for orientation,
placement, etc.
•
The transmit signal has been checked with a spectrum analyzer at RF
connector, X602 and was found to be too low or non-existent.
•
The VCO is running correctly.
•
The power amplifier is getting a correct VBATRF supply via L809.
•
Mjoelner's supply voltages VR1A, VR2, VR3, VR4, VR5 & VR7 are all
working correctly.
Is Signal at
Is Signal at
NO
Change
900
TX_GSM on
TX_850_OUT
L801
L801 OK?
on L801 OK?
YES
Is Signal at
NO
Antenna pin
of Z601 ok?
YES
Change X602
C650.
RF Connector
Check Antenna
Switch Control
YES
Lines. Do they
match the results
in the table?
NO
Check L701
Change
Check L701,
Check L703
and L702.
Antenna
L702 & L703.
and L813 OK?
OK?
Switch
OK?
NO
Replace
Inductors
Issue 1 05/2004
Company Confidential
START
Is Signal
Is Signal
Is EGSM
YES
YES
at C881
at C834
TXIN signal
TXIN signal
OK?
OK?
at R828 OK?
at R805 OK?
R825
NO
900
Probe VPD_850 Signal
Probe VPD_900Signal
on R818 and set Power
on R818 and set Power
Level to 19 using Phoenix.
Level to 19 using Phoenix.
Is Pulse Pk-Pk 2.8V?
Is Pulse Pk-Pk 2.8V?
NO
YES
Replace PA
Check / Replace
Check / Replace
R825, R824 and
R826,R827,R828,
R805, C820, C821
R826.
C820,C821
YES
KEY
Test using
Spectrum Analyzer
Copyright © 2004 Nokia Corporation
Company Confidential
START
900
Is 850
NO
Is Signal at
Is Signal at
R733 OK?
C733 OK?
YES
Is signal at
R805
L807 OK?
YES
YES
Is Signal at V802
Collector OK?
NO
Is VTXB
Is VTXB
900
_850 OK?
_900 OK?
NO
YES
Test using
Check /
Oscilloscope
Inspect
6b - RF Troubleshooting
NO
Are TX I & Q on
C715 & C716. OK?
YES
Are digital I & Q
Are TXP &
signals OK on
TXC visible?
J123 & J214?
J202 and J203?
YES
NO
NO
NO
TXP
TXC
Is VR2
2.8V on
C731?
NO
YES
Check Z701 &
Change
Biasing components
Mjoelner
Check V802 &
associated components
End
Action
RH-29
NO
YES
NO
Change
UPP
Change
UEM
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Troubleshooting
