User Guide

PAMS Technical Documentation 6 - Troubleshooting
NPE-4
Original ãNokia Corporation. Page 6-23
RF Troubleshooting
Introduction
Measurements should be done using Spectrum Analyzer with high-frequency high-
impedance passive probe (LO-/reference frequencies and RF-power levels) and Oscillo-
scope with a 10:1 probe (DC-voltages and low frequency signals).
The RF-section is build around one ASICS Hagar (N600). For easier troubleshooting, this
RF troubleshooting document is divided into sections.
Before changing Hagar, please check the following things: Supply voltages are OK and
serial communication are coming to Hagar (See Baseband troubleshooting document).
Please note that the grounding of the PA-module is directly below PA-module so it is
difficult to check or change. Most RF semiconductors are static discharge sensitive!
So ESD protection must be taken during repair (ground straps and ESD soldering irons).
The Hagar IC is moisture sensitive so parts must be pre-baked prior to soldering.
Apart from key-components described in this document here are a lot of discrete compo-
nents (resistors, inductors and capacitors) which troubleshooting is done by checking if
soldering of the component is done properly, for factory repairs (checking if it is missing
from PCB). Capacitors can be checked for shortening and resistors for value by means of
an ohmmeter, but be aware in-circuit measurements should be evaluated carefully.
Please be aware that all measured voltages or RF levels in this document are rough
figures. Especially RF levels varies due to different measuring equipment or different
grounding of the used probe.
All tuning must be done with Phoenix Service Software, version 02.90.001, or later.