User Guide

PAMS
Technical Documentation
NHD–4
Disassembly & Troubleshooting
Page 40
Original 11/97
RF Input Power
881.62 MHz CW
(dBm)
Voltage Drop
Across R16
(RX_ICT)
(mV)
–45 11
–50 14
–55 17
–60 21
–65 25
–70 30
–75 37
–80 45
–85 56
–90 68
–95 83
–100 99
–105 113
DC Voltage Checks
Check the following DC voltages with the –65 dBm 881.62 MHz CW signal
still fed into the phone and the Service Software CDMA Troubleshooting
Mode initiated.
•The bias voltage on the BFILCT2 IC (N2), pin 4 should be approx 3.10 V.
If not, first ensure that the phone is in the CDMA Troubleshooting Mode. Check the
VBBFIL supply voltage at the collector of V203, or CDCONT (N201), pin 15, or C223.
It should be approximately 3.15 V.
•The bias voltage on the BFILCT2 IC (N2), pin 8 should be approx 3.05 V
If not, first ensure that the phone is in the CDMA Troubleshooting Mode. Check the
VRXD_R supply voltage at pin 4 of V206, or CDCONT (N201), pin 15, or C223. It
should be approximately 4.50 V.
•The bias voltage on the CDAGCR IC (N1), pin 13 should be approx 4.40 V.
If not, first ensure that the phone is in the CDMA Troubleshooting Mode. Check the
VRXD_R supply voltage at pin 4 of V206, or CDCONT (N201), pin 15, or C223. It
should be approximately 4.50 V.
•Measure the voltage drop across R17 at the RX_IREF line, (one probe on
either side of this resistor). The voltage drop should be approx 330 mV.
If not, first ensure that the phone is in the CDMA Troubleshooting Mode. Ensure that
the –75 dBm 881. 62 MHz CW signal is fed into the receiver. Perform the DC Volt-
age checks on that module to determine if there is a problem with the AGC circuitry.