User Guide

NSW-4
Disassembly & Troubleshooting
PAMS Technical Documentation
Page 13
Issue 1 Final Draft
08/00
 Nokia Mobile Phones Ltd.
Flash programming doesn’t work
The flash programming is carried out via the pads accessible from the
back of the phone (using service accessories).
Flash programming doesn’t work
FLASH (D201) VBB is 2.8V (C203),
NO
YES
OK
check
VCXO G850
YES
PURX (J140) master reset=”1”(2.8V)
RFC (J250) 19.44 MHz sine wave
Clock signal: 700mV Vpp typ.
COBBACLK (J210) 9.72MHz sq.wave
clock signal 2.80 Vpp
VBB (C166) 2.8 V
VR1 (C158) 2.8 V
NO
See section ”Phone is totally dead”
YES
Sleep clock SLCLK (J157)
square wave 32 kHZ
NO
Check sleepclock circuitry
NO
Faulty circuit N150
or over loaded PurX line
YESYES
Check the following lines:
FBUSTXD line: J114–>MAD1
FBUSRXD line: J113–>MAD1
M2BUS line: J112 to MAD1
Check also pullup and pulldown
resistors
R209, R210, R212
There could be open pins in circuits D200, D201, D202
(open joints may be detectable with microscope).
If not the PCB or D202, D200, D201, N150 is faulty
VBAT > 3.0 V
C154, C155, C190
SRAM (D200) VBB is 2.8 V (C200),
FLASH VPP is > 2.8 V (C202)
Check control lines of SRAM and FLASH:
RAMSelX (J207), RPMSelX (J208)
MCURDX and MCUWRX (X200 pins 19 and 18)
e.g. there is voltage spikes when trying to write
and read something to SRAM and FLASH
OK
OK