User Guide

PAMS Technical Documentation Troubleshooting Instructions
NSB-5
Issue 1 03/01 Nokia Mobile Phones Ltd. Page 11
Power Doesn’t Stay on or Phone is Jammed
If this kind of fault occurs after flash programming, there may be open pins on ICs or
other discrete components. Solder joints on discrete capacitors and resistors and open
joints on components with pins, such as D302 (SRAM), should be checked first. The sol-
dered joints of ICs D300 (MAD2WD1), D301 and D303 (FLASH), N200 (COBBA_GJP), and
N100 (CCONT) are difficult to visually inspect since these components are CSP or uBGA
style packages.
A quick and easy way to test the solder joints on CSPs is to apply a small amount of pres-
sure to the top of the package while powering-up the phone. If the phone powers-up
while applying pressure to a specific component (e.g., MAD), then it can be assumed that
that component has faulty solder joints.
Normally, the power will be switched off by CCONT (N100) after 30 seconds if the
watchdog of the CCONT cannot be served by software. In order to verify if watchdog is
updated, verify that X400 pin-2 is high and at the same time X400 pin-13 toggles. In
normal cases, there is a short burst of pulses every 8 seconds.
The power-off function of CCONT can be prevented by connecting a short circuit wire
from R413 (end towards N100) to ground.