Nokia NEM-4 Series Troubleshooting Instructions page 22

NEM-4
BB Troubleshooting
When the flashing of the device does not succeed, but powering is OK, follow these
instructions.
Note: The absence of clocks may indicate that the device (put phone to LOCAL mode
when the sleep is not allowed or press buttons so that phone is not in sleep mode) is in
sleep mode. Make sure that the device is not in sleep during clocks measuring.
IMPORTANT: Clock signals have to be measured with 1MΩ (or greater) probes!
Measure signal from J170. This should be 26Mhz clock signal. See RF Troubleshooting for
further information.
Check the crystal oscillator (B190) is oscillating at 32.768kHz frequency. If not change
B190. If ok, measure SleepClk from test point from capacitor C521. Frequency should be
the same 32.678kHz (see Figure 2, "Sleep clock," on page 20 below.) If not change UEM.
ADSP Clock (12MHz sine wave) can be measured from oscillator B550.
Charging checking
Use the BL5-C battery and JBV-1/MJF-26 calibration set to test charging. (NOTE: power
supply cannot be charged if it not has a current sinking capability.) When you are charg-
ing totally empty battery, remember that start-up charging might take a little bit longer
time than normal. During this time display is blank.
If charger is not NMP approved type and its current and voltage is not within NMP
charger window then software does not start charging and there is "NOT CHARGING" on
the display. Voltage should be between 5.3V - 9.5V and current between 200mA –
Page 6(a)-20
Company Confidential
Figure 2: Sleep clock
Copyright  2003 Nokia Corporation
Company Confidential
CCS Technical Documentation
(Testpoint J124)
(Capacitor C521)
Issue 1 09/2003