Nokia 5110 Service Manual
PAMS
Technical Documentation
NSE–1
Disassembly & Troubleshooting Instructions
Page 13
Original 03/98
Phone register failure
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
N100
Analog reference voltage Vref is 1.5 V
at pin 9 of Cobba (N250)
NO
Check
R270, R271
YES
Supply voltage VCP (N100 pin 32) > 4.8 V
Supply voltage VRX (N100 pin 9) > 2.7 V
Supply voltage VSYN_1 (N100 pin 15) > 2.7 V
Supply voltage VSYN_2 (N100 pin 4) > 2.7 V
during the receiving slot
Supply voltage VTX (N100 pins 11, 20) > 2.7 V
during the transmitting slot
YES
NO
Check
N100, D200
Synthesizer lines: SEna (N620 pin 56),
SClk (N620 pin 54)
SData (N620 pin 55)
pulses 0 –> 1 during receiving slot
NO
Check
D200
YES
RF control lines: RxC (N250 pin 18) 0 –> 2.3 Vmax during receiving slot
AFC (N250 pin 19) 0 – 1.2 V typ. during receiving slot
NO
Check
N250
YES
Analog data signal RxIP (N250 pin 22) 0–> 1.5 V DC during receiving slot
Analog data signal RxIN (N250 pin 22) 0–> 1.5 V DC during receiving slot
Used benefit signal is biased to DC and its amplitude is 50 mVpp
nominal and frequency is 13 MHz
NO
Check
N250 if DC is failed
Check
RF part if benefit signal is failed
YES
DAX signal (N250 pin 48) pulses 1 –> 0 during receiving slot
NO
Check
N250
RF control lines: TxC (N250 pin 17) 0 –> 2.3 Vmax during transmit slot
TxP (D200 pin 176) 0–>1 (2.8 V) during transmit slot
YES
Check
N250 if TxC is failed
Check
D200 if TxP is failed
NO
YES
Analog data signals: TxIN (N250 pin 13) 0–> 0.8 V DC during transmit slot
TxIP (N250 pin 14) 0 –>0.8 V DC during transmit slot
TxQN (N250 pin 15) 0 –>0.8 V DC during transmit slot
TxQP (N250 pin 16) 0 –>0.8 V DC during transmit slot
Used benefit signal is biased to DC and its amplitude is 300 mVpp
nominal and frequency is 67 kHz
NO
Check
N250
YES
Check
RF part