Nokia 9000i Service Manual page 270

RAE/RAK–1N
Faultfinding/Disassembly
3.3.1.1 CPU Fault
If the CPU does control the PWMOUT signal correctly, even though the
signal is disconnected from the PDA power unit, then it is likely that the
CPU is at fault.
3.3.1.2 Check PDA Power Unit
The LCDVEE output of the PDA power unit should change within the legal
limits according to the PWMOUT signal duty factor. If the PWMOUT signal
is controlled OK, but the LCDVEE voltage doesn't change, then check the
PDA power unit. Check components R86, C90 and R83.
3.4 Check LCD Test–Patterns
In order to check the functionality of every pixel on the LCD, various test
patterns can be produced by selecting the LCD test in the service
software.
3.5 Test–Patterns OK?
If all the pixels on the LCD toggle, the LCD test can be considered to have
been successful. If there are some pixels / patterns that are not OK, then
return to 3.1.4
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After Sales
Technical Documentation
Original, 05/97