Nokia RA-2 Guide

Issue 1 09/04 COMPANY CONFIDENTIAL
Copyright © 2004 Nokia. All Rights Reserved.
Nokia Customer Care
7 - RF Description and
Troubleshooting

Issue 1 09/04 COMPANY CONFIDENTIAL 2
Copyright © 2004 Nokia. All Rights Reserved.
RA-2/3 Nokia Customer Care
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Issue 1 09/04 COMPANY CONFIDENTIAL 3
Copyright © 2004 Nokia. All Rights Reserved.
RA-2/3
7 - RF Description and Troubleshooting Nokia Customer Care
Table of Contents Page No
CMT RF................................................................................................................. 5
Top-level description.......................................................................................... 5
RA-2 test point locations................................................................................... 6
Test points ......................................................................................................... 8
RF implementation in RA-2/3........................................................................... 11
Frequency plan .............................................................................................. 11
RF block diagram ........................................................................................... 12
Antenna switch module (ASM) ....................................................................... 12
DC characteristics .......................................................................................... 13
Regulators................................................................................................. 13
DC supply currents.................................................................................... 13
Typical current consumption...................................................................... 14
Power distribution diagram........................................................................ 15
RF characteristics ............................................................................................ 16
Channel numbers and frequencies ................................................................ 16
RF Troubleshooting.......................................................................................... 17
Receiver description and troubleshooting........................................................ 17
Rx front end ................................................................................................... 17
Antenna ......................................................................................................... 17
Receiver characteristics ................................................................................. 18
General instructions for Rx troubleshooting ................................................... 19
Troubleshooting diagram for GSM850 receiver......................................... 23
Troubleshooting diagram for GSM900 receiver......................................... 24
Troubleshooting diagram for GSM1800 receiver....................................... 25
Troubleshooting diagram for GSM1900 receiver....................................... 26
Transmitter description and troubleshooting.................................................... 27
Power amplifier .............................................................................................. 27
RF ASIC Helgo .............................................................................................. 27
AFC function .................................................................................................. 28
Transmitter characteristics ............................................................................. 28
General instructions for Tx troubleshooting ................................................... 28
Transmitter troubleshooting diagram......................................................... 30
HELGO IC troubleshooting diagram.......................................................... 31
PA and antenna switch troubleshooting diagram ...................................... 32
Pictures of transmitter signals ................................................................... 33
Additional information for EDGE troubleshooting ............................................ 35
Transmitter EDGE troubleshooting diagram.............................................. 36
HELGO EDGE troubleshooting diagram................................................... 37
PA and antenna switch EDGE troubleshooting diagram........................... 38
Pictures of EDGE transmitter signals ............................................................. 39
Synthesizer description and troubleshooting................................................... 43
Frequency synthesizers ................................................................................. 43
General instructions for synthesizer troubleshooting ..................................... 43
Troubleshooting diagram for synthesizer .................................................. 44

Issue 1 09/04 COMPANY CONFIDENTIAL 4
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RA-2/3
7 - RF Description and Troubleshooting Nokia Customer Care
Table of Contents Page No
Pictures of synthesizer signals.................................................................. 45
Frequency Lists .............................................................................................. 48
GSM850 .................................................................................................... 48
GSM900 (including EGSM900)................................................................. 49
GSM1800 .................................................................................................. 50
GSM1900 .................................................................................................. 51
RF tunings after repairs ................................................................................... 52
WLAN RF Description....................................................................................... 53
RF operating modes ........................................................................................ 54
Transmitter ..................................................................................................... 54
Receiver ......................................................................................................... 55
Synthesizer .................................................................................................... 55
Antenna .......................................................................................................... 55

Issue 1 09/04 COMPANY CONFIDENTIAL 5
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RA-2/3
7 - RF Description and Troubleshooting Nokia Customer Care
CMT RF
■ Top-level description
The RF module performs the necessary high frequency operations of the GSM850/EGSM900/
1800/1900 tripleband (EDGE) engine. Both the transmitter and receiver have been implement-
ed by using direct conversion architecture which means that the modulator and demodulator
operate at the channel frequency.
The core of the RF is an application-specific integrated circuit, Helgo. Another core component
is a power amplifier module which includes two amplifier chains, one for GSM850/EGSM900
and the other for GSM1800/GSM1900.
Other key components include
• 26 MHz VCTCXO for frequency reference
• 3296-3980 MHz SHF VCO (super high frequency voltage controlled oscillator)
• Antenna switch module (ASM)
• Four SAW filters
The control information for the RF is coming from the baseband section of the engine through
a serial bus, referred later on as RFBus.
The whole RF circuitry is located on one side of the 8-layer PWB.
EMC leakage is prevented by using a metal cans. The RF circuits are separated into two
blocks.
• PA, ASM, LNA, baluns for Rx/Tx and Rx/Tx SAWs.
• Helgo RF IC, VCO + balun, VCTCXO, baluns and EGSM Rx filter
The RF transmission lines constitute of striplines and microstriplines after PA.

RA-2/3
Nokia Customer Care 7 - RF Description and Troubleshooting
6 COMPANY CONFIDENTIAL Issue 1 09/04
Copyright © 2004 Nokia. All Rights Reserved.
■ RA-2 test point locations
Figure 1: Top view
RefClk C6302
N6300 pin3 C6307
N6302 pin3
C6310
N6303 pin3
C6314
N6300 pin5
R6305
D6310
pins 5&6
C 5837
V7802 pins1,6,4
J7510
J7511
Z7800
J7501
J7502
J7503
J7509
G7500
Z7809
L7809
L7810
Z7808
L7823
L7822
L7830
L7805
C7707
L7702
L7700
L7709
L7710
R7715
R7711
C7535
C7536
R7522
J7 450
C7551
C7520
C7510
C7553
C7506
R7500
R7525
R7725
C7713
C7714
J2809
PURX
J28 00
C2006
R2004
C2005
N4490 pin3&4
R6043
R4800
Power 2.8
Power 1.8
VCTRL
R4418 R4415
C2107
R4101
J4100
C2108
R2106
C2104
C2105
C4104 R4100
C4105
R2126
J2803
R2000
R2125
L2330
L2333
L2331
L2332
L2334
L2335
C2210
C2204
C2881
C2232
C2202L2206
J2 280
R2902
G7501
R4802
J28 00
J2809
J8120
J4802
C4800
C4801
J4815
C4203
L4201
C4819
C4211
L4202
C4204
R4808
C5083
C5089
R4801
J4803
C5000
R5001
C5001
J4805
C6428
R6304
C6433
N6301
pin3
G6400
pin3
N6303 pin4
R6402
N6400
pins 39-42
R6428
C6446
R6405
C6401
N6405
pin2
C6456
C6455
C6404
R6404
C6407
C6445
R6411

Issue 1 09/04 COMPANY CONFIDENTIAL 7
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RA-2/3
7 - RF Description and Troubleshooting Nokia Customer Care
Figure 2: Bottom view
RF
J2031
J2032 J2033
30J17
J3 610
J3103
J3101
J31 80
J3109
J3104
J3102
8J31 2
J3180
J3181
J2121
J2120
J2122
20J20
J2021
J0222
J51 00
J1150
102J5
J1053
J5104
50J15
J5106
J5107
5108J
J4413 J4414
J3100
GND
Battery
Production
testpoints
Trace
IHF
Mic
Charge
N4400
B-Cover
switch
SIM
MMC
Zocus
Bluetooth
N7100
X2021 pins 6&7
X2021 pins
11-14
R4422
C5200
R5202
R2001
C2037
C2038
L2020
R4202
C4202
N6402
pins 1&3

RA-2/3
Nokia Customer Care 7 - RF Description and Troubleshooting
8 COMPANY CONFIDENTIAL Issue 1 09/04
Copyright © 2004 Nokia. All Rights Reserved.
■ Test points
Table 1: Rx test points
Table 2: Antenna switch test points
Table 3: Helgo serial interface test points
Signal name: Ref:
LNA_VCC V7802
LNA_IN V7802
LNA_P V7802
RXI J7510
RXQ J7511
Signal name: Ref:
VANT_1 Z7800
VANT_2 Z7800
VANT_3 Z7800
GSM_Rx Z7800
DCS_Rx Z7800
PCS_Rx Z7800
TX_IN_EGSM/850 Z7800
Signal name: Ref:
RFBusClk J7501
RFBusEna1 J7502
RFBusData J7509
Reset J7503

Issue 1 09/04 COMPANY CONFIDENTIAL 9
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RA-2/3
7 - RF Description and Troubleshooting Nokia Customer Care
Table 4: Synthesizer test points
Table 5: GSM900/850 Rx helgo input test points
Table 6: GSM1800 Rx helgo input test points
Table 7: GSM1900 Rx helgo input test points
Table 8: Tx PA input test points
Table 9: Tx filter/balun input test points
Signal name: Ref:
VCO_out G7500
VCTCXO_out G7501
Ref:
RX filter Z7809
Inductor L7809
Inductor L7810
Ref:
Filter Z7808
Inductor L7823
Inductor L7822
Inductor L7830
Ref:
Inductor L7805
Signal name: Ref:
Rfin_900/850 C7707
Rfin_1800/190 L7702
Signal name: Ref:
RfinP_900 L7700
RfinM_900 L7700

RA-2/3
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10 COMPANY CONFIDENTIAL Issue 1 09/04
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Table 10: PA control signal test points
Table 11: Rx test points
RfinP_1800_1900 C7709
RfinM_1800_1900 C7710
Signal name: Ref:
VPCTRL_900 R7715
VPCTRL_1800_1900 R7711
TXIM C7535
TXIP C7535
TXQM C7536
TXQP C7536
TXC R7522
TXP J7504 (test pad)
Signal name: Ref:
VR1 C7551
VR2 C7520
VR3 C7583
VR4 C7510
VR5 C7553
VR6 C7506
VR7 R7500
VrefRF01 R7525
VBAT C7725
VTXB_900 C7713
VTXB_1800_1900 C7714

Issue 1 09/04 COMPANY CONFIDENTIAL 11
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RA-2/3
7 - RF Description and Troubleshooting Nokia Customer Care
■ RF implementation in RA-2/3
Frequency plan
The RF frequency plan is shownbelow.The VCO operates at the channel frequencymultiplied
by two or four depending on the frequency band of operation. This means that the baseband
modulated signals are directly converted up to the transmission frequency and the received RF
signals directly down to the baseband frequency.
Figure 3: RF frequency plan

RA-2/3
Nokia Customer Care 7 - RF Description and Troubleshooting
12 COMPANY CONFIDENTIAL Issue 1 09/04
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RF block diagram
Antenna switch module (ASM)
Figure 4: ASM
Helgo

Issue 1 09/04 COMPANY CONFIDENTIAL 13
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RA-2/3
7 - RF Description and Troubleshooting Nokia Customer Care
DC characteristics
Regulators
The transceiver baseband section has a multi function analog ASIC, UEM, which contains
among other functions six pieces of 2.78 V linear regulators anda 4.8 V switching regulator. All
the regulators can be controlled individually by the 2.78 V logic directly or through a control reg-
ister. Normally, direct control is needed because of switching speed requirement: the regula-
tors are used to enable the RF-functions which means that the controls must be fast enough.
The use of the regulators can be seen in the power distribution diagram which is presented in
Figure 6, “Power distribution diagram,” on page 15.
The seven regulators are named VR1 to VR7. VrefRF01 is used as a reference voltage for
Helgo.
The regulators (except for VR7) are connected to the Helgo. Different modes of operation can
be selected inside the Helgo according to the control information coming through the RFBus.
DC supply currents
Figure 5: DC power supplies

RA-2/3
Nokia Customer Care 7 - RF Description and Troubleshooting
14 COMPANY CONFIDENTIAL Issue 1 09/04
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Typical current consumption
The table shows the typical current consumption in different operation modes.
Operation mode Current
consumption Notes
Power OFF < 10 uA Leakage current (triple band
PA)
Rx, EGSM900/GSM850 75 mA, peak
Rx, GSM1800/GSM1900 70 mA, peak
Tx, power level 5, EGSM900/
GSM850 1700 mA, peak
Tx, power level 0, GSM1800/
GSM1900 1000 mA, peak

Issue 1 09/04 COMPANY CONFIDENTIAL 15
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RA-2/3
7 - RF Description and Troubleshooting Nokia Customer Care
Power distribution diagram
Figure 6: Power distribution diagram
HELGO
LNA
GSM1800/
1900

RA-2/3
Nokia Customer Care 7 - RF Description and Troubleshooting
16 COMPANY CONFIDENTIAL Issue 1 09/04
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■ RF characteristics
Channel numbers and frequencies
System Channel number Tx frequency Rx frequency Unit
GSM850 128< =n <=251 F= 824.2+0.2* (n -
128) F= 869,2+0.2* (n -128) MHz
GSM900 0 < =n <=124 F = 890 + 0.2 * n F = 935 + 0.2 * n MHz
975<= n <= 1023 F= 890+0.2* (n -1024) F= 935+0.2* (n -1024) MHz
GSM1800 512 <= n <= 885 F=1710.2+0.2*(n-512) F=1805.2+0.2*(n-512) MHz
GSM1900 512 <= n <=810 F=1850.2+0.2*(n-512) F=1930.2+0.2*(n-512) MHz

Issue 1 09/04 COMPANY CONFIDENTIAL 17
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RA-2/3
7 - RF Description and Troubleshooting Nokia Customer Care
RF Troubleshooting
All measurements should be done using a spectrum analyzer with a high-frequency high-im-
pedance passive probe (LO-/reference frequencies and RF power levels) and an oscilloscope
with a 10:1 probe (DC-voltages and low frequency signals).
The RF section is build aroundone RF ASIC (HELGO N7500). For easier troubleshooting, this
RF troubleshooting document is divided into sections.
Before changing HELGO, please check that both supply voltages and serial communication
coming from baseband to HELGO are OK. Please note that the grounding of the PA module is
directly below the PA module, so it is difficult to check or change.
Most RF semiconductors are static discharge sensitive! Therefore ESD protection must be tak-
en care of during repair(ground straps andESD soldering irons). HELGO and PA are moisture
sensitive so parts must be pre-baked prior to soldering.
Apart from key components described in this document there are a lot of discrete components
(resistors, inductors and capacitors) of which troubleshooting is done by checking if the solder-
ing of the component is done properly (for factory repairs checking if it is missing from the
PWB). You can check capacitors for shortening and resistors for value by means of an ohm-
meter, 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 vary due to different measuring equipment or different grounding of the
probe used. When using an RF probe use a pair of metallic tweezers to connect the probe
ground to the PWB ground as close to the measurement point as possible.
■ Receiver description and troubleshooting
Each receiver path is a direct conversion linear receiver. From the antenna, the received RF-
signal is fed to a front end module where a diplexer first divides the signal into two separate
paths according to the band of operation: either lower, GSM850/EGSM900 or upper,
GSM1800/GSM1900 path.
Most of the receiver circuitry is included in Helgo.
Rx front end
The front end features include:
• Antenna 50 ohm input
• RXs single outputs
• TXs single 50 ohm inputs
• 3 control lines from Helgo
Antenna
The RA-2/3 GSM850/EGSM900/GSM1800/GSM1900 transceiver features an internal anten-
na. There are two triple-band antennas: one for RA-2 and one for RA-3.

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18 COMPANY CONFIDENTIAL Issue 1 09/04
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Receiver characteristics
Item Values, GSM850/EGSM900/1800/1900
Type Direct conversion, Linear, FDMA/TDMA
LO frequencies 3476...3576/3700...3840 MHz / 3610...3760
MHz/3860...3980 MHz
Typical 3 dB bandwidth +/- 91 kHz
Sensitivity min. - 102 dBm (normal condition)
Total typical receiver voltage gain (from
antenna to Rx ADC) 86 dB
Receiver output level (RF level -95 dBm) 230 mVpp, single-ended I/Q signals to Rx
ADCs
Typical AGC dynamic range 83 dB
Accurate AGC control range 60 dB
Typical AGC step in LNA 30 dB GSM1800/GSM1900
25 dB GSM850/EGSM900
Usable input dynamic range -102... -10 dBm
RSSI dynamic range -110... -48 dBm
Compensated gain variation in receiving
band +/- 1.0 dB

Issue 1 09/04 COMPANY CONFIDENTIAL 19
Copyright © 2004 Nokia. All Rights Reserved.
RA-2/3
7 - RF Description and Troubleshooting Nokia Customer Care
General instructions for Rx troubleshooting
To start Rx troubleshooting:
1. Connect test jig to a computer with a DAU-9S cable or to a FPS-8 flash prom-
mer with an XCS-4 modular cable.
Make sure that you have PKD-1 dongle connected to the computer’s parallel port.
2. Connect a DC power supply to the module test jig with an FLC-2 cable.
3. Set the DC supply voltage to 3.6 V.
4. Connect an RF cable to the RF connector of the module test jig (MJ-19) and to
RF signal generator.
5. Set the phone module to test jig and start Phoenix service software.
6. Initialize connection to the phone. (Use FBUS driver when using DAU-9S and
COMBOX driver when using FPS-8).
7. From the File menu, choose “Choose Product”.
8. From the list, select RA2/RA-3.
9. From the toolbar, set operating mode to "Local".
10.From the Testing menu, choose “RF Controls”.
11.In the “RF Controls” window:
- Select band “GSM850", “GSM 900", "GSM 1800" or “GSM1900” (Default =
"GSM900" RA-2, Default= “GSM850” RA-3)
- Set Active unit to "Rx" (Default = "Rx")
- Set Operation mode to "Burst" (Default = "Burst")
For continuous mode:
- Set Operation mode to "Continuous"
- Set AGC to "12: FEG_ON + DTOS_ON + BB_30=Vgain60” (maximum gain set-
ting used in normal mode) (Default = "14: FEG_ON + DTOS_ON +
BB_42=Vgain72")
- Set Rx/Tx channel to 190 on GSM850, 37 on GSM900 band,700 on GSM1800
band or 661on GSM1900 (Defaults)
12.Apply
881,6671 MHz (channel 190 + 67,710 KHz offset),
942.46771 MHz (channel 37 + 67.710 kHz offset),
1842.86771 MHz (channel 700 + 67.710 kHz offset) or
1960.06771 MHz (channel 661 + 67.71 kHz) –90 dBm signal
to the RF connector (remember to compensate for cable attenuation).
When measuring with an oscilloscope on "RXI" or "RXQ", you should see the fol-
lowing screens on a working GSM900, GSM1800 or GSM1900 receiver:

RA-2/3
Nokia Customer Care 7 - RF Description and Troubleshooting
20 COMPANY CONFIDENTIAL Issue 1 09/04
Copyright © 2004 Nokia. All Rights Reserved.
Figure 7: Rx I/Q signal, burst mode, input level –90dBm
• Receiver I or Q burst mode signal (channel 37) measured from test point RXI
or RXQ with 942.46771 MHz signal, input level –90dBm at RF-connector.
Correct signal amplitudes approximately:
GSM850~170mVpp
GSM900~170mVpp
GSM1800~140mVpp
GSM1900~160mVpp
Signal part frequency 67.7kHz sine.
DC level of signal part is 1.35V. DC level can variate about +/-100mV between