User Guide

Technical Documentation
NHB–3
PAMS
Troubleshooting
Original 26/97
Page 17
Power circuitry
D192
VCTCXO
ASIC MCUPSL
VA
VA2
XRESET
VREF
VL2
VL1 MCU CLK
RESET
IRQX
VBAT 5.5...8 V
CHRGDET 1.5 V
DETIN
XPWROFF 2 pulses / sec
CLK 26 MHz
CLK 26 MHz
ON
C113
TXD
R166
BUFFER
5,20
11
12
14
1
2
24
846
116
45
99
69
10
77
5,42 66
43
9
5 V=ON
XPWROFF
PSL
– Output voltages must be stay at high state at least 1.5 s when power is
switched on.
– If no; check C113.
– If it is OK; replace PSL.
– If the XRESET line doesn’t rise check CHRDET and DETIN. The voltage
value at these pins should be 1.5 V.
ASIC
– When XRESET and CLK are supplied to the ASIC but MCUCLK or RESETX
to the MCU are not supplied; replace ASIC.
MCU
– If MCUCLK and RESETX are supplied from ASIC but TXD line (MBUS)
doesn’t rise and solderings of the MCU are good; replace MCU.
– If TXD pin (MCU) goes to high but doesn’t stay at high state at least 1.5 s.
The power of the phone can be hold on following way:
– Connect PSL pin 14 to the ground.
– Lift MCU pin 77 IRQ0 and connect it to VL1.
Now its possible to use PCLocals software.