PAMS
Technical Documentation
NSC/W–1/3
Disassembly & Troubleshooting Instructions
Page 11
Original 11/99
The phone doesn’t register to the network or phone doesn’t make a call
Phone doesn’t register to the network
or
phone doesn’t make a call
YES
Analog supply voltage VCOBBA is >2.7 V
at pin 7,12 ... of Cobba (N250)
NO
YES
Check
N250
Analog reference voltage Vref is 1.5 V
at pin 9 of Cobba (N250)
NO
Check
R256
YES
YES
NO
Synthesizer lines: SEna2 (N880 pin 13 ),
SClk (N880 pin 11)
SData (N880 pin 12)
pulses 0 –> 1 during off burst
NO
YES
AFC (N250 pin 13) 0 – 1.2 V typ. during receiving burst
NO
YES
Analog data signal IF2AN (N250 pin 8) –> 0.6 Vpp, 0–>2.2 V DC
Analog data signal IF2AP (N250 pin 7) –> 0.6 Vpp, 0–>2.2 V DC
NO
Check
N250 if DC is failed
Check
RF part if benefit signal is failed
YES
DAX signal (N250 pin 62) pulses 1 –> 0 during receiving slot
NO
Check
N250
TX control lines: TxC (N750 pin 11) 0 –> 2.3 Vmax during transmit burst
TXA (N750 pin 2) goes 0–>1 (2.8 V) during modulation
YES
Check
N250 if TxC is failed
Check
D202 if TXA is failed
NO
YES
Analog data signals: TxIN (N250 pin 21) 0–> 0.8 V DC during transmit slot
TxIP (N250 pin 20) 0 –>0.8 V DC during transmit slot
TxQN (N250 pin 19) 0 –>0.8 V DC during transmit slot
TxQP (N250 pin 18) 0 –>0.8 V DC during transmit slot
Used IQ signals are biased to 0.8V DC and AC amplitude is 400 mVpp
max, frequency is 12 kHz max
NO
Check
N250
YES
Check
RF part
RX AMPS: VR1, VR2, VR4/VR8, VR6, V5V
RX DAMPS: VR1, VR2, VR4/8, VR6, V5V
TX AMPS: VR3, VR5, VR7, TXPWR3
TX DAMPS: VR3, VR5, VR7, VR7_bias, TXPWR3
TX TDMA: VR11
RX TDMA: VR1, VR6, V5V, VR9, VR10, VR12
Note; Each VR is to be checked only once!
MAD D202
CCONT N150
PENTA N702
MAD
COBBA
D202
N250
TXLX are low during PL7 to PL2 and high during PL10 to PL 8
AGC1 (N250 pin 14) 0 ––>2.3 V max during receiving burst
Digital data signal IF2DN (N250 pin 10) –>170 mVpp typ,
Digital data signal IF2DP (N250 pin9) –>170 mVpp typ, 0–>2.7 V DC
Frequency is 450 MHz
0–> 2.7 V DC
TXLX1 (D202 pin 96) and TXLX2 (D202 pin 98) 0–> 1 (2.8 V)