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NSM–2
Disassembly & Troubleshooting Instructions
Phone is totally dead
The phone doesn't take current at all when the power switch is pressed or
when the watchdog disable pin (X001 pin 11) is grounded. Make sure that
the battery voltage you use is within the specification, i.e. 3.11 .. 4.2 V. If
the voltage is lower, hardware of CCONT (N100) prevents power on.
IF battery voltage is inside the specification Change the CCONT.
Flash programming fails
The flash programming can be done via panel connector X001 or via
dedicated PCB pads. In production, the first programming is done via
panel connector. After this, the panel connector is cut away, thus the pro-
gramming must be done via PCB pads visible through the shield under
the battery. The main difference between these is that FLASH–program-
ming voltage is produced differently. The fault finding diagrams for flash
programming is shown in the start up sequence picture.
In flash programming error cases the flash prommer can give some in-
formation about a fault. The fault information messages could be:
– MCU doesn't boot
– Serial clock line failure
– Serial data line failure
– External RAM fault
– Algorithm file or alias ID not found
– MCU flash Vpp error
Power doesn't stay on or phone is jammed
If this kind of fault has come after flash programming, there are most
probably open joints in ICs. Solder the joints of ICs. Normally the power
will be switched off by CCONT (N100) after 30 seconds if the watchdog of
the CCONT can not be served by software. This updating can be seen
with an oscilloscope at CCONTCSX (J104). In normal case there is a
short pulse from "1" to "0" every 8 seconds. The power off function can be
prevented by connecting WDDIS (R118 edge side head) to ground.
Because of the underfill, check the supply voltages, clock signals and
power up sequence. If power on sequence fails, there are some open
connections under MAD or compomemory. If all seems to be correct, it is
best way to erase the flash memory and try to put new software to phone.
Contact Service on the phone display
This fault means that software is able to run and thus the watchdog of
CCONT (N100) can be served. Selftest functions are run when power is
switched on and software is executed from flash. If any of the selftests
fails, a "contact service" text is shown on display.
MCU self tests are devided to those executed while power up (start up
tests) and ones that can be executed with connected PC. The tests and
included items are as follows:
Page 16
E Nokia Mobile Phones Ltd.
PAMS Technical Documentation
Issue 1 12/1999
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Table of Contents
Troubleshooting
