Rf Troubleshooting; Introduction To Rf Troubleshooting - Nokia NHM-7 Series Troubleshooting Manual

Hide thumbs Also See for NHM-7 Series:

Table of Contents

PAMS Technical Documentation

RF Troubleshooting

Measurements should be done using spectrum analyzer with high–frequency

high–impedance passive probe (LO–/reference frequencies and RF power lev-

els) and oscilloscope with a 10:1 probe (DC–voltages and low frequency sig-

nals).

The RF–section is build around one RF–ASIC (HAGAR N600). Before chang-

ing HAGAR, please check following things: Supply voltages are OK and serial

communication coming from baseband to HAGAR.

Note: Grounding of the PA module is directly below PA module making it diffi-

cult to check or change. Most RF semiconductors are static discharge sen-

sitive! So ESD protection must be taken care of during repair (ground straps

and ESD soldering irons). HAGAR and PA are moisture sensitive and must be

pre–baked prior to soldering.

Troubleshooting discrete components (resistors, inductors and capacitors) is

done by checking component soldering. Capacitors can be checked for short-

ening and resistor values using an ohmmeter, but remember in–circuit mea-

surements are evaluated with caution.

Remember that all measured voltages or RF levels in this document are rough

figures. Especially RF levels vary due to different measuring equipment or dif-

ferent probe grounding used . When using RF probe it is good to use metal

tweezers to connect probe ground to PWB ground as close to measurement

point as possible.

,VVXH

Troubleshooting and Tuning Instructions

1RNLD &RUSRUDWLRQ

NHM-7

3DJH

Table of Contents