User Guide

CCS Technical Documentation 7 - Troubleshooting Instructions
RH-26
Issue 1 02/04 ©Nokia Corporation Page 5
RF Troubleshooting
Measurements should be done using a spectrum analyzer with a high-frequency high-
impedance passive probe (LO-/reference frequencies and RF power levels) and an oscillo-
scope with a 10:1 probe (DC-voltages and low frequency signals)
The RF-section is build around one RF-ASIC (HELGO N500).
Most RF semiconductors are static discharge sensitive! So ESD protection must be
taken care of during repair (ground straps and ESD soldering irons).
Apart from key components described in this document there are a lot of discrete com-
ponents (resistors, inductors and capacitors). Their troubleshooting is done by checking
that the soldering of the component is done properly (for factory repairs checking if it is
missing from the PWB). Capacitor 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 note that all measured voltages or RF levels in this document are rough figures.
Especially RF levels vary due to different measuring equipment and different grounding
of the probe used. When using the RF probe, use metallic tweezers to connect the probe
ground to the PWB ground as close to measurement point as possible.