User Guide

NSW-4
Disassembly & Troubleshooting
PAMS Technical Documentation
Page 14
Issue 1 Final
Draft 08/00
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Power doesn’t stay on or the Phone is jammed
If this kind of fault has come after flash programming, there are most
probably open pins in ICs. The solder joints of ICs: MAD1 (D202), Flash
(D201) and SRAM (D200) are to be checked at the extent possible (by
microscope from the side of PCB and lightly pressing components while
switching power on).
Normally the power will be switched off by CCONT (N150) after 32 sec-
onds, if the watch-dog of the CCONT can not be served by software. The
watch-dog updating can be seen by oscilloscope at J154 (DataselX) of
CCONT. In normal case there is a short pulse from ”1” –> 0 every 8 sec-
onds. The power off function of CCONT can be prevented by connecting
a short circuit wire from WDDISX (CCONT E4 (J150)) to ground (J151).
Power doesn’t stay on or phone is jammed
FLASH (D201) VBB is 2.8V (C203)
NO
N150 is faulty
VBAT is OK =
3.8V
YES
YES
PURX (J152) master reset = ”1” (2.8 V)
NO
Sleep clock SLCLK
square wave 32 kHz
NO
YES
Faulty circuit N150
or over loaded PURX line
check sleep
clock circuitry
(B150, R157...)
YES
YES
YES
Connect short circuit wire from
OK
CCONT (N150) watchdog is served?
J154 pulses 1 –> 0)
YES
Software is able to run
after few seconds, check
BSI (X100 to C167) and
BTEMP (X100 to C168)
lines
If power is switched off
Open pins or faulty circuit:
D202, D200, D201, N150
RFC (J255) 19.44 MHz sine wave
Clock signal: 700 mV Vpp typ.
COBBACLK (J210) 9.72 MHz square wave
clock signal 2.80 Vpp
Watchdog J150 to ground J151
Check VCXO G850
NO