User Guide

Nokia Customer Care
RM-1
RF Troubleshooting
Company Confidential
Copyright © 2004 Nokia. All rights reserved
7A - 49
Issue 1
RF-levels should be about the same on both capacitors. Remember to select the correct
band also in Phoenix.
• PCS1900: Connect the probe to C7523 or C7525. The RF level should be roughly -85…-
90 dBm during RX period when input signal in GSM antenna connector is -50 dBm.
RF-levels should be about the same on both capacitors. Remember to select the correct
band also in Phoenix.
• NOTE! If RSSI-values are correct only in one or two GSM-bands but RX ASIC HINKU
(N7500) is receiving RF-power correctly from the GSM antenna connector in all three GSM-
bands, typically this means that Hinku ASIC (N7500) is faulty or the ASIC is badly soldered.
For example: RSSI-values are not realistic in EGSM900-band but are ok in other bands and
HINKU is receiving RF-power correctly in all bands. Then it’s quite clear that HINKU (N7500)
is faulty or badly soldered and the component should be replaced.
3.2.1.1 Is Z7503 (antenna switch) working correctly?
• GSM receiver has to be active before measurements. Procedure is explained in chapter
“GSM RX chain activation for manual measurements”.
• Connect an RF-generator to the GSM-antenna connector
• Set RF-generator frequency as following:
- EGSM900: 942.46771 MHz (Channel 37)
- DCS1800: 1842.86771 MHz (Channel 700)
- PCS1900: 1960.06771 MHz (Channel 661)
• Measurements can be done with a spectrum analyser and an RF probe. Remember to make
correct frequency settings to the spectrum analyser (Centre frequency should be set to the
same frequency as the RF-generator). RBW and VBW = 10 kHz, Span = 0 kHz, sweep time 5
ms.
• RF-signals in this measurement are pulsed and video triggering is needed in the spectrum
analyser (software dependent issue. With some phone softwares these signals are
constant in “Local” mode and triggering is not needed).
• EGSM900: Connect the probe to L7504. The RF level should be roughly -75 dBm during RX
period when input signal in GSM antenna connector is -50 dBm. RF-levels should be about
the same on both ends of the inductor. Remember to select the correct band also in
Phoenix.
• DCS1800: Connect the probe to L7505. The RF level should be roughly -85 dBm during RX
period when input signal in GSM antenna connector is -50 dBm. RF-levels should be about
the same on both ends of the inductor. Remember to select the correct band also in
Phoenix.