User Guide

RH-21 Company Confidential
Troubleshooting Nokia Customer Care
Page 8  2004 Nokia Corporation. Issue 2 07/2004
1 Power key pressed
• After 20ms, UEM enters RESET MODE if VBAT>Vmstr+
• VFLASH1, Vana, Vcore, Vio, and VR3 goes high
• VCTCXO enabled by VR3 -> RFClk 19.44 MHz running
2Purx released
• Purx released by UEM, UEMINT goes high for 100 ms, SleepX goes high, and
SleepClk (32 KHz) starts running.
3 Software running
• Default value for Vcore is 1.5 volts and, if software is running, Vcore will rise to
1.8 volts
• Cbus (1.08MHz) and Dbus clocks start running
Phone does not start up normally or does not stay on
Note: In the case of power-up faults, it is not possible to force the phone on by disabling the watchdog.
Instead, measurements should be taken immediately when the power key is pressed or when the bat-
tery voltage is connected to the phone (local / test mode).
The easiest way to check if the software is running when the phone takes an abnormal
amount of current is to measure the cbusclk and Vcore.
The Dbus clock (programmable 9.72MHz) is not automatically visible in the test and local
modes.