Nokia Customer Care
Appendix A: RF Troubleshooting
A-26
Company Confidential
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2005 Nokia. All rights reserved
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Disconnect the power supply from the phone and use an ohmmeter to check that inductor is
conducting DC.
3.1.1.1.2 RFBUS signals ok?
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GSM receiver has to be active before RFBUS signals can be measured. Procedure is explained in
section “GSM RX chain activation for manual measurements”. Also WCDMA/GSM transmitter and
WCDMA receiver activation can be used for the measurement but then RFBUS -signals don’t
necessarily look like in figures mentioned below.
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Measurements can be performed with an oscilloscope and a probe. Check all five RF BUS signals:
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RFBUSDAT
: Connect the probe to J7504. Typical RFBUSDAT -signal is shown in section 6.5.9.3
“
”
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RFBUSCLK
: Connect the probe to J7505. Typical RFBUSCLK -signal is shown in sections 6.5.9.1
“
RFBUSCLK and RFBUSENA (GSM RX)
”
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RFBUSENA
: Connect the probe to J7506. Typical RFBUSENA -signal is shown in section 6.5.9.2
“
RFBUSCLK and RFBUSENA (GSM RX)
”
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RXRESETX
: Connect the probe to J7515. RXRESETX -signal is a constant 2 V DC-signal after GSM or
WCDMA transceiver has been activated the first time after phone boot up. The level of this signal
should be about 0 V before transceiver activation.
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TXRESETX
: Connect the probe to J7517. TXRESETX -signal is a constant 2 V DC-signal after GSM or
WCDMA transceiver has been activated the first time after phone boot up. The level of this signal
should be about 0 V before transceiver activation.
3.1.1.1.2.1 RAP3G (or Vinku or Hinku) faulty?
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RAP3G (D2800) cannot be replaced.
3.1.1.1.3 Vinku (N7501) regulator voltages VREG1, VREG2 ok?
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GSM transmitter has to be active before VREG1 and VREG2 voltages can be measured. Procedure is
explained in section “Transmitter troubleshooting.”
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Measurements can be done with an oscilloscope and a probe.
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VREG1: Connect the probe to C7543
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VREG2: Connect the probe to C7548 (or C7547)
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VREG1 and VREG2 voltage levels should be 2.65 – 2.86 V. Typical value is 2.7 V.
3.1.1.1.3.1 Vinku (N7501) RB_EXT voltage ok?
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GSM transmitter has to be active before Vinku’s RB_EXT voltage can be measured. Procedure is
explained in section “Transmitter troubleshooting”.
