Energy Management Troubleshooting; Device Does Not Stay On; General Power Checking - Nokia NHL-2NA Series Troubleshooting Instructions

NHL-2NA

Energy management troubleshooting

Device does not stay on

If the device is switched off without any visible reason, there may be problems in the fol-
lowing areas:
• UEM watchdog problem (WD is not updated by SW)
• BSI line problem (BSI line is floating => contact failure)
• Battery line problem
• Soldering problem
The most likely reason is UEM WD (watchdog), which turns the device off after about 32
seconds if SW is jammed.
This may be caused by a SW problem, UPP_WD2 problem (Not server by SW), UEM, AEM
or memory malfunctions.
The following tests are recommended:

• General power checking

• Clocks
• Memory testing
• Serial Interface
If there is something wrong in BSI line, the device seems to be dead after the power key
is pressed. However the regulators of the device are on a few seconds before the power-
down.
This mode can easily be detected from the current consumption of the device. After a
few seconds the current consumption drops almost to 0 mA.
In this case check components listed below or soldering:
Battery connector X002
Grip connector X001 (especially pin number 27)
Hotbar soldering X380 (especially pin number 5)
EMI-filter Z383 (especially pins number A4 and E4)
UEM D190 (pin number C2)
If phone boots to TEST or LOCAL mode with normal battery, BSI or Btemp or both lines
are short circuited to ground. Check varistors, EMI-filter and filtering capacitors, which
are located to BSI and Btemp lines.
General power checking
Use service tool FLA-21. Battery voltage should be atleast 3.6V. After phone disassembly,
use module jig MJS-9Q.
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CCS Technical Documentation
Issue 1 07/02