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NSD-6
Disassembly/Troubleshooting Instructions
between 3V and 5V. The phone uses VSIM as the 3V FLASH programming voltage, so it
should remain off unless the phone is being flashed. Valid voltages are 2.8V to 3.2V, and
it can be checked at TPD7 (or TP33 on PWB).
A/D Conversion
CCONT contains a 10–bit A/D converter that is multiplexed between 8 different inputs.
They are used mainly for battery and charger monitoring. The 8 inputs are Vbat (battery
voltage), ICHAR (charger current), VCHAR (charger voltage), BSI (battery type), BTEMP
(battery temperature), VCXOTEMP (PA temperature), RSSI (AMPS receive signal strength),
and EAD (accessory detection). These readings can be accessed through the service soft-
ware. Check for shorts or opens on the resistor networks connected to these signals if the
flash align test software reports that they are out of range.
Watchdog
CCONTs watchdog circuitry consists of an eight bit down counter that causes CCONT to
power down when zero is reached. The counter may be reset by loading a new, non–zero
value into the watchdog register via CCONTs serial bus. It is difficult to verify the watch-
dog function, but the serial bus may be verified.
There is a watchdog disable pin which allows the watchdog timer to expire without
shutting down the phone, but this pin is mainly used as one of the methods to turn on
CCONT from power off mode. While the phone power key is pressed, this pin should be
pulled low and can be checked at TPD 35 (R325).
The watchdog can be disabled by pulling down the above mentioned pin(WDDISX) by
installing a 0 Ohm resistor at R307, and removing R325.
Serial bus
Since the serial bus is used to control almost all of CCONTs functions, any shorts or open
circuits on these three lines would cause CCONT to be completely nonfunctional. The
main symptoms are the following:
CCONT will turn on when the power key is pressed (verify this by checking Vbb), but will
then power off after 32 seconds. All three serial bus sig nals (CCONTCSX,
UIF_CCONT_SDIO, and UIF_CCONT_SCLK) should toggle when attempting to write to a
CCONT register.
Note: If the LCD does not come on during this time, however, it may indicate that the
serial bus is functional, but phone does not have valid flash code.
PENTA
PENTA supplies power to the RF section. It has 5 independently switchable regulators
that are controlled via separate enable pins. There is also a common enable pin that must
be active in order to turn on any of the regulators. Each of the regulators, P1–P5, should
have output voltages between 2.7V and 2.85V (2.8V nominal). These can be checked at
the following test points.
a) P1 – TPD18
Page 10
Nokia Mobile Phones Ltd.
PAMS Technical Documentation
Issue 1 04/01
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Table of Contents
Troubleshooting
