User Guide

NSW-4
Disassembly & Troubleshooting
PAMS Technical Documentation
Page 39
Issue 1 Final Draft
08/00
 Nokia Mobile Phones Ltd.
Power control loop
Power control section is basically similar for both bands, except for that
both bands have their own directional coupler and detector. The power
control is actually made in EROTUS IC.
Is DETO vs. output
power and TXC
OK?
See chart below.
Check power
control components
near N700
Press N700
Change N700
Change N700
Is TXLX functionality
OK ?
TXLX are LOW on
power levels PL 2…7
Check PIN diode
bias components.
Check BB controls.
(BaseBand)
Is V929, V930
voltage drop about
0.3–0.4 V
Check V930, V929
Check bias circuit
around diodes.
Y
N
N
Y
N
Note !
See DETO vs. Output power
curve
Note:
1. DETO and TXC will be
about same in each mode.
2. TXA is high during modulation.
3. TXLX signals will draw about
4mA current in high state.
TYPICAL DETECTED VOLTAGES AT POWER LEVELS PL2…PL10
800D 1900
D
Pout TXC LB–DETO Pout TXC UB–
DETO
PL dBm dac mV PL dBm dac mV
2 26.8 250 1650 2 26.8 124 1478
3 23.5 77 1350 3 23.0 27 1275
4 20.0 –40 1120 4 20.0 –53 1120
5 16.0 –127 930 5 16.0 –128 937
6 12.0 –187 840 6 12.0 –177 831
7 8.0 –228 750 7 8.0 –215 762
8 4.0 –188 840 8 4.0 –205 768
9 0.0 –229 740 9 0.0 –253 693
10 –4.0 –290 650 10 –4.0 –329 531