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CCS Technical Documentation
RF troubleshooting
Repairing instructions for RF Unit
Introduction
Measurements should be done using spectrum analyzer and high-frequency probe (Local
and reference frequencies and RF-power levels in intermediate stages of chain). Oscillo-
scope is used to measure DC-voltages and low frequency signals. Multimeter is also use-
ful measurement equipment in faultfinding. Also cellular tester is needed in order to
perform tests mentioned in this document.
External RF connector is implemented to design improving reliability of the measurement
results and should be in use when it is reasonable.
RF-section is mainly build around of SAFARI GTE IC (N801). The RF block has separate
external filters, UHF and VHF synthesizer, Power Amplifier, front-end and up converter
circuit for both frequency band.
To simplifying troubleshooting, this RF troubleshooting document is divides into three
bigger sections: Receiver-, Transmitter and Synthesizer parts. The tolerance is specified
for critical signals/voltages.
Before changing single ASICs or components, please check the following things:
1 The soldering and alignment marks of the ASICs
2 Supply voltages and control signals are OK
The PA-module is static discharge sensitive! ESD protection must be used when deal-
ing with PA-IC (ground straps and ESD soldering irons). The PA is also moisture sensitive
components and it is important to follow additional information about handling the
component. So wear EDS protected clothes and shoes whenever handling the radio mod-
ule unit! Also wrist-grounding strap should be used.
The shield lid must be always replaced with new one after it is opened. Plate bands under
shield lid could be cut but always bend plate ends downwards after repairing. Plate ends
should NOT touch shield lid after lid is installed. Note also that there are no short circuits
caused by plate ends on PWB.
Issue 1 11/02
ãNokia Corporation
RH-13
Troubleshooting
Page 27
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Table of Contents
Troubleshooting
