Nokia RM-42 Service Manual

Also see for RM-42: Service manual

Contents

Nokia Customer Care Appendix A: RF TroubleshootingA-84Company ConfidentialCopyright © 2005 Nokia. All rights reservedexplained in section “Transmitter troubleshooting”.• Measurements can be done with a spectrum analyser and an RF probe. Spectrum analyser RBW =VBW = 10 MHz, Span ≤ 2 MHz, sweep time 100 ms. Spectrum analyser centre frequency should beset according the used TX channel (see section “Frequency mappings”).• Connect the RF probe to R7520. The RF-level should be about the same on both ends of theresistor. Check output level with 0 dBm (“0”) power level.- Power level (“0”) – Output level should be about -45…-48 dBm• Check if output levels of Vinku are as expected.4.1.2.1.1 RF operating voltage VBAT_ASIC ok?• See section “RF operating voltage VBAT_ASIC ok?”4.1.2.1.2 Vinku (N7501) regulator voltages VREG1, VREG2 ok?• WCDMA transmitter has to be active before VREG1 and VREG2 voltages can be measured. Procedureis explained in section “Transmitter troubleshooting”. Measurements can be done with anoscilloscope and a probe.• VREG1: Connect the probe to C7543• VREG2: Connect the probe to C7548 (or C7547)• VREG1 and VREG2 voltage levels should be 2.65 – 2.86 V. Typical value is 2.7 V.4.1.2.1.2.1 Vinku (N7501) RB_EXT voltage ok?• WCDMA transmitter has to be active before Vinku’s RB_EXT voltage can be measured. Procedure isexplained in section “Transmitter troubleshooting”.• Measurement can be done with an oscilloscope and a probe.• Connect the probe to R7521.• RB_EXT voltage should be 1.325 – 1.375 V.4.1.2.1.2.1.1 VREFRF01-voltage ok?• Measurement can be done with an oscilloscope and a probe.• Connect the probe to R7503.• VREFRF01 voltage should be 1.325 – 1.375 V. Typical value is 1.35 V.4.1.2.1.2.1.1.1 Desolder R7503. Is VREFRF01 voltage still wrong?• Remember to solder a new component to R7503 pads after measurement.4.1.2.1.2.1.1.1.1 Capacitors C7518, C7520 and C7570 working correctly?