Customer Care Solutions Technical Documentation 6(b) - RF Troubleshooting and Manual Tuning Guide ISSUE 2 01/2004 COMPANY CONFIDENTIAL Copyright © 2003 Nokia. All Rights Reserved.
NHL-10 CCS Technical Documentation RF Troubleshooting This page has been deliberately left blank 2 COMPANY CONFIDENTIAL Copyright © 2003 Nokia. All Rights Reserved.
NHL-10 RF Troubleshooting CCS Technical Documentation Table of Contents Page No Introduction ................................................................................................................... 5 General troubleshooting ................................................................................................ 6 RF Key Component Placement ..................................................................................... 7 Receiver Troubleshooting ....................................
NHL-10 CCS Technical Documentation RF Troubleshooting This page has been deliberately left blank 4 COMPANY CONFIDENTIAL Copyright © 2003 Nokia. All Rights Reserved.
NHL-10 RF Troubleshooting CCS Technical Documentation Introduction This document describes the troubleshooting and RF tuning of Nokia 6600 (NHL-10). In general, two types of measurements have to be performed during the troubleshooting and repair of phones: • RF measurements shall be done with a spectrum analyzer, either connected directly to the RF connector of the board (“antenna point”), or used together with a high-frequency probe to measure RF signals at points along the TX or RX chain.
NHL-10 CCS Technical Documentation RF Troubleshooting General troubleshooting The first step of fault-finding should always be a visual inspection. Carefully inspect the RF area using a microscope and look for cracks, solder bridges, dry joints, missing components, components that have partially come off and other anomalies. Capacitors can be checked to see that they are not short-circuited, and inductors that they are not open circuits. Also check that power supply lines are not short-circuited, i.e.
NHL-10 RF Troubleshooting CCS Technical Documentation RF Key Component Placement The following figure shows the key components of the RF section. Figure 1: RF Key Components shows key components of the RF section.
NHL-10 CCS Technical Documentation RF Troubleshooting Figure 3: RF Key Components 8 COMPANY CONFIDENTIAL Copyright © 2003 Nokia. All Rights Reserved.
NHL-10 RF Troubleshooting CCS Technical Documentation Receiver Troubleshooting General Description Figure 4: Receiver Signal Path The receiver is a direct conversion, triple-band linear receiver. NHL-10 uses Mjølner RFIC with external VCO. The received RF signal from the antenna/RF connector goes into the RF antenna switch where the signal is fed to the E-GSM900, GSM1800 or GSM1900 path. For each band, a RX bandpass SAW filter with unbalanced input and balanced output follows.
NHL-10 CCS Technical Documentation RF Troubleshooting fections. DCN2 centres the differential signal with respect to the common mode reference voltage of 1.35V. Differential, filtered I/Q-signals are finally fed to the sigma-delta ADC’s in the UEM. Further filtering in the digital domain occurs in the sinc decimation filter and DSP based FIR filters General Instructions for RX Troubleshooting Connect the phone to a PC with DAU-9S cable and dongle and follow the following instructions.
NHL-10 RF Troubleshooting CCS Technical Documentation • Apply a signal with frequency of: EGSM: 942.467MHz (channel 37 + 67.710KHz offset), GSM1800: 1842.867MHz (channel 700 + 67.710KHz offset), GSM1900: 1960.067MHz (channel 661 + 67.710KHz offset), and a power level of –80dBm to the RF connector (remember to compensate for the cable loss). • In RSSI reading click Read now. The resulting RSSI level should be –80dBm in each band.
NHL-10 CCS Technical Documentation RF Troubleshooting Measuring the RX module manually using Oscilloscope and Spectrum Analyzer Spectrum Analyzer level values depend on the probe type and should be validated using a known good NHL-10 sample. The levels that are given here are measured using a high frequency probe. Measuring with Oscilloscope on RXINN or RXQINN (J606 –608) and RXID or RXQD (J211 – J212) is recommended only if RSSI reading does not provide enough information.
NHL-10 RF Troubleshooting CCS Technical Documentation The input freq/level of the signal generator is 942.467710MHz, -60dBm. Figure 5: Fault finding chart for GSM900 Apply -60 dBm 942.4 MHz, offset 67.71 kHz from generator to antenna connector YES EGSM chain functional Check RSSI using Phoenix Does it match Sig Gen Output level ? NO NO Is L.
NHL-10 CCS Technical Documentation RF Troubleshooting Probed RX I/Q signals J606 - 609 with signal setting to 942.467710MHz, -60dBm. Note that the display is the same for both GSM1800/1900 bands as well. • Signal amplitude: 456mV • DC offset: 1.36V • Frequency: approx 67KHz GSM1800 • Start Phoenix Service Software and establish a connection to the phone. • Select File -> Scan Product Ctrl R. • Wait until the phone software version is shown in the lower part of the screen.
NHL-10 RF Troubleshooting CCS Technical Documentation Figure 6: Fault finding chart for GSM1800 Apply -60 dBm 1842.8 MHz, offset 67.71 kHz from generator to antenna connector YES EGSM chain functional Check RSSI using Phoenix Does it m atch Sig Gen Output level ? NO NO Is L.
NHL-10 CCS Technical Documentation RF Troubleshooting The input freq/level of signal generator is 1960.067710MHz, -60dBm Figure 7: Fault finding chart for GSM1900 Apply -60 dBm 1960 MHz, offset 67.71 kHz from generator to antenna connector YES EGSM chain functional Check RSSI using Phoenix Does it match Sig Gen Output level ? NO NO Is L.
NHL-10 RF Troubleshooting CCS Technical Documentation Measurement points in the Receiver Figure 8: Measurement points at the RX SAW filters –Z602, Z603, Z604 Figure 9: Measurement points for I/Q baseband signals ISSUE 2 01/2004 COMPANY CONFIDENTIAL Copyright © 2003 Nokia. All Rights Reserved.
NHL-10 CCS Technical Documentation RF Troubleshooting Figure 10: Measurement points for RX I/Q digital signals Figure 11: Measurement points at the Antenna switch 18 COMPANY CONFIDENTIAL Copyright © 2003 Nokia. All Rights Reserved.
NHL-10 RF Troubleshooting CCS Technical Documentation Tuning of the RX Using Phoenix RX Channel Select Filter Calibration This calibration is calibrating the Baseband filter inside Mjølner ASIC. It is done by internally measuring a prototype filter, for this reason the calibration is done once, not separately for all three bands. • Select Tuning -> RX Channel Select Filter Calibration. • Press Tune. RX channel select filter calibration is finished.
NHL-10 CCS Technical Documentation 20 • Press Start. • Follow the instructions in the pop–up window. • Press OK. COMPANY CONFIDENTIAL Copyright © 2003 Nokia. All Rights Reserved.
NHL-10 RF Troubleshooting CCS Technical Documentation • Press Save & Continue. • Press OK and continue. For GSM1900 just repeat the same procedure as for GSM900/GSM1800. If the calibration is OK, you should see “RX calibration was completed successfully” on the display. ISSUE 2 01/2004 COMPANY CONFIDENTIAL Copyright © 2003 Nokia. All Rights Reserved.
NHL-10 CCS Technical Documentation RF Troubleshooting RX Band Filter Response Compensation The Rx Band Filter Response Compensation has nine steps for each band. The RF Band Filter Response Compensation requires an external signal generator. 22 • Select Tuning -> RX Band Filter Response Compensation. • Select Manual. COMPANY CONFIDENTIAL Copyright © 2003 Nokia. All Rights Reserved.
NHL-10 RF Troubleshooting CCS Technical Documentation • Follow the instructions given in the following pop-up window. There are nine steps in all. • After completing the nine steps of calibration at nine frequencies, press Save & Continue. ISSUE 2 01/2004 COMPANY CONFIDENTIAL Copyright © 2003 Nokia. All Rights Reserved.
NHL-10 CCS Technical Documentation RF Troubleshooting Repeat all steps as for GSM900 for the GSM1800 band. Follow all the instructions in the popup window. Repeat the procedure for GSM1900. The tuning is completed. 24 COMPANY CONFIDENTIAL Copyright © 2003 Nokia. All Rights Reserved.
NHL-10 RF Troubleshooting CCS Technical Documentation Transmitter Troubleshooting General Description A simple block diagram of the TX part of the phone is shown in the following figure. The voice or data signals to be transmitted come from the UEME IC in the BB (Base Band) area, and go to the Mjølner IC, where they are up-converted to RF. The TX signals going from UEME to Mjølner are called the IQ signals, and consist of two balanced signals { TXIN, TXIP } and { TXQN, TXQP }, i.e.
NHL-10 CCS Technical Documentation RF Troubleshooting Figure 2: GSM RF area Directional Coupler Power Detector Circuit ASM Mjolner Power Amplifier Up-mixer bias networks (EGSM/DCS/PCS) EGSM Pre-Amp DCS/PCS Balun EGSM SAW Filter Preparation for Fault Finding 1 Place phone (mechanics removed) on module jig. 2 Connect the module jig to the PC via a DAU-9S cable. 3 Connect the module jig to the power supply (4.2V).
NHL-10 RF Troubleshooting CCS Technical Documentation 13 Set RX/TX Channel to 37 for GSM900, 700 for GSM1800 or 661 for GSM1900. 14 Set TX PA Mode to Free. 15 Set TX Power Level to 5 in GSM900, otherwise to 0. Phoenix should now look as shown in the following figure. ISSUE 2 01/2004 COMPANY CONFIDENTIAL Copyright © 2003 Nokia. All Rights Reserved.
NHL-10 CCS Technical Documentation RF Troubleshooting Fault-finding chart: TX-BB interface and control signals Figure 3: Fault finding chart of BB-TX interface & some control signals Start Cont3 VR3 Cont2 Cont1 Using a multimeter, check power supply lines to Mjolner: Line VR1a VR2 VR3 VR5 VR6 VR7 Voltage Test Points 4.75V 2.78V 2.78V 2.78V 2.78V 2.
NHL-10 RF Troubleshooting CCS Technical Documentation Fault-finding chart: RF side of transmitter In Phoenix select: Active unit=TX, Operation Mode=Burst, TxPA Mode=Free, TxData Type=Random, and for each band: GSM900, channel=37, PL5 GSM1800, channel=700, PL0 GSM1900, channel=661, PL0 PA EGSM input OK Measure power at RF connector: GSM900: Power between 31 & 35dBm GSM1800 & GSM1900: Power between 28 & 32dBm NOK Signal found? OK Yes OK NOK Check all power levels Search for output signal with 500MHz
NHL-10 CCS Technical Documentation RF Troubleshooting Transmitter Tuning Introduction In the transmitter, there are two kinds of tunings that can be performed. These are IQ-tuning and power level tuning. In general, different repairs require different tunings. In order to decide which tuning is necessary after a repair, it is important to understand well the functionality of the repaired circuit. In general, it is recommended that if any TX component is changed, both these tunings are done.
NHL-10 RF Troubleshooting CCS Technical Documentation Figure 1: Phoenix set-up Figure 2: Phoenix set-up After opening the two before-mentioned windows, Phoenix should look as shown in the following figure. ISSUE 2 01/2004 COMPANY CONFIDENTIAL Copyright © 2003 Nokia. All Rights Reserved.
NHL-10 CCS Technical Documentation RF Troubleshooting Figure 3: Phoenix set-up The following table summarises the settings of the RF control window for the IQ tuning of the three bands. Table 2: RF Control Window Settings Band TX Data Type TX Power Level RX/TX Channel GSM900 All 1 5 37 GSM1800 All 1 0 700 GSM1900 All 1 0 661 To start the IQ tuning, press Start in the IQ Tuning window. 32 COMPANY CONFIDENTIAL Copyright © 2003 Nokia. All Rights Reserved.
NHL-10 RF Troubleshooting CCS Technical Documentation The spectrum analyzer screen should now look similar to that of the figure below (GSM900 case). Figure 4: Spectrum analyzer screen shot when performing IQ tuning RBW 3 kHz Ref Lvl 33.35 dBm VBW 3 kHz 35 dBm 897.33229000 MHz 1 SWT 3 s Marker 1 [T1] 35 27.5 dB Offset RF Att Unit 1 [T1] 30 30 dB dBm 33.35 dBm A 897.33229000 MHz 2 [T1] 20 -6.76 dBm 897.40000000 MHz 3 [T1] -10.74 dBm 897.
NHL-10 CCS Technical Documentation RF Troubleshooting After reducing the amplitude of the frequency components at marker 2 and 3 to a minimum, press Save & Continue. The EGSM tuning has now been completed. Now, using the spectrum analyzer settings of Table 1, and the RF control settings of Table 2, follow exactly the same procedure to perform IQ tuning in the GSM1800 and GSM1900 bands.
NHL-10 RF Troubleshooting CCS Technical Documentation Table 3: Spectrum Analyzer Settings EGSM900 GSM1800 GSM1900 Center frequency 897.4MHz 1747.8MHz 1880MHz Frequency span Zero-span Zero-span Zero-span Resolution Bandwidth 1MHz 1MHz 1MHz Video Bandwidth 1MHz 1MHz 1MHz Sweep Time 1ms 1ms 1ms Trigger Type Video Video Video Trace Type Clear/Write Clear/Write Clear/Write Detector Type Max Peak Max Peak Max Peak In Phoenix, select Tuning -> TX Power Level Tuning.
NHL-10 CCS Technical Documentation RF Troubleshooting Figure 6: Phoenix power level tuning menu Connect the module jig RF output to the measurement instrument. In the EGSM band the power must be tuned in both high and low TX PA mode. In the two upper bands (GSM1800 and GSM1900) there is only one mode. For each band, tune the power by adjusting the coefficient in the Tx Power Level Tuning window in Phoenix until the target level is reached (measured on the spectrum analyzer).
NHL-10 RF Troubleshooting CCS Technical Documentation Figure 7: Phoenix screen shot The next figure shows the spectrum analyzer screen shot associated with the above Phoenix screen shot. Figure 8: Spectrum analyzer screen short during power level tuning ISSUE 2 01/2004 COMPANY CONFIDENTIAL Copyright © 2003 Nokia. All Rights Reserved.
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