Nokia 6680 RM-36, Service Manual

Page: 346 / 479

Nokia Customer Care Appendix A: RF Troubleshooting
A-100
Company Confidential
Copyright © 2005 Nokia. All rights reserved
• Measurements can be done with an oscilloscope, a probe and signal generator.
•
WCDMA receiver has to be active before RX IQ-signals can be measured. Procedure is explained in
section “Receiver troubleshooting”.
• Apply –50 dBm RF-signal (unmodulated) from a signal generator to the module jig antenna
connector and use frequency 2140.1 MHz (Channel 10700)
• Remember to change the correct RX channel also to Phoenix “RX control” window!
•
Check RX I and RX Q -signals in following test points:
-
RX I (positive): Connect the probe to test point J7508
-
RX I (negative): Connect the probe to test point J7509
-
RX Q (positive): Connect the probe to test point J7510
-
RX Q (negative): Connect the probe to test point J7511
• Signal in all four test points should be about the same. Output should be a sine wave with
frequency 100 kHz and amplitude about 650 mV.
• Change the signal generator to frequency 2142.0 MHz (Channel 10700)
• Signal in all four test points should be about the same. Output should be a sine wave with
frequency 2.0 MHz and amplitude about 550 mV.
4.2.4.1 RF operating voltage VBAT_ASIC ok?
• See section “RF operating voltage VBAT_ASIC ok?”
4.2.4.2 RFBUS signals ok?
•
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.
• Measurements can be performed with an oscilloscope and a probe. Check all five RF BUS signals:
-
RFBUSDAT : Connect the probe to J7504. Typical RFBUSDAT -signal is shown in section 6.5.9.3
"RFBUSDAT (GSM RX)" .
-
RFBUSCLK : Connect the probe to J7505. Typical RFBUSCLK -signal is shown in figures “RFBUSCLK
(GSM RX)” and “ RBUSCLK and RFBUSENA (GSM RX) ”.
-
RFBUSENA : Connect the probe to J7506. Typical RFBUSENA -signal is shown in the figure “ RFBUSCLK
and RFBUSENA (GSM RX)” .
-
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.
• 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