Nokia RM-57, Руководство по обслуживанию

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Appendix A: RF Troubleshooting Nokia Customer Care
Company Confidential
Copyright © 2005 Nokia. All rights reserved
A-70
3.5.2.3 Replace Vinku (N7501)
3.5.3 Does GSM PA (N7502) get correct DET_SW_G -voltage from Vinku ASIC (N7501)?
• GSM transmitter has to be active before DET_SW_G voltage can be measured. Procedure is
explained in section “Transmitter troubleshooting”.
•
Measurement can be done with an oscilloscope and a probe.
• Connect the probe to C7595. Notice: C7595 is a non-assembled component so the probe
should be connected to the pad that can be still found from the PWB.
• DET_SW_G voltage should be about 2.8 V while TX burst and 0 V otherwise.
3.5.3.1 Replace Vinku (N7501)
3.5.4 Are components in GSM power control loop in place and working ok?
R7516 and C7559
•
Disconnect the power supply from the phone and use an ohmmeter to check that C7559 is
not short-circuited. If short-circuit is found replace the capacitor.
•
Check R7516 resistance value with an ohmmeter and replace resistor if needed.