Nokia 2270, 2272, 2275, 2285 Manuale Di Servizio
RH-3
Troubleshooting - RF
CCS Technical Documentation
Page 54
Nokia Corporation Confidential
Issue 1 06/2003
TX RF AGC (Cell)
This tuning characterizes the RF AGC
curve by entering PDM values to the RF
AGC and measuring the output power.
curve by entering PDM values to the RF
AGC and measuring the output power.
Check Jedi (N601). Also check D400, which
generates the PDM signals. Check AGC PDM
voltages. Troubleshoot the rest of the cell
transmitter if needed.
generates the PDM signals. Check AGC PDM
voltages. Troubleshoot the rest of the cell
transmitter if needed.
TX Gain Comp (Cell)
This tuning ensures that the value of
TxdBCtr correctly corresponds to the
absolute TX output power. On the mid
channel, with TxdBCtr set to a specified
value, G_Offset is adjusted so that the
output power is -8 dBm, and that value
of G-Offset is recorded (which is an
absolute value) in the next tuning. The
output power in dBm is recorded in this
tuning. After this is done on the mid
channel, the channel is changed to each
of the other channels, and output power
is reported. (G_offset is not adjusted on
the other channels as it was on the
center channel, just the output power is
recorded).
TxdBCtr correctly corresponds to the
absolute TX output power. On the mid
channel, with TxdBCtr set to a specified
value, G_Offset is adjusted so that the
output power is -8 dBm, and that value
of G-Offset is recorded (which is an
absolute value) in the next tuning. The
output power in dBm is recorded in this
tuning. After this is done on the mid
channel, the channel is changed to each
of the other channels, and output power
is reported. (G_offset is not adjusted on
the other channels as it was on the
center channel, just the output power is
recorded).
Set the phone to local mode and program it
to Cellular (or PCS) CDMA RX/TX mode on
channel 384 (or 600 for PCS) using the
Main Mode window. Using the Phoenix RF
Tuning window, choose mode = RF Tuning,
and choose this test. Adjust G_Offset in the
"Values” dialog box line until the TX output
power (measured on the RF connector with
a spectrum analyzer) is equal to -8.0 dBm
+/- 0.5 dB. Use the G_Offset limit range as a
guide to which values to enter.Once this is
done on the center channel, change to each
of the other channels, and record the power.
Do not adjust G_Offset on the other chan-
nels, just record the power. It should be
within the limits listed in the tuning results
file.
Channel Cell PCS
Low 991 25
LowMid 107 200
MidLow 245 400
Mid 384 600
MidHigh 512 800
HighMid 660 1000
High 799 1199*
*1199 not a voice channel, but used in tun-
ing.
to Cellular (or PCS) CDMA RX/TX mode on
channel 384 (or 600 for PCS) using the
Main Mode window. Using the Phoenix RF
Tuning window, choose mode = RF Tuning,
and choose this test. Adjust G_Offset in the
"Values” dialog box line until the TX output
power (measured on the RF connector with
a spectrum analyzer) is equal to -8.0 dBm
+/- 0.5 dB. Use the G_Offset limit range as a
guide to which values to enter.Once this is
done on the center channel, change to each
of the other channels, and record the power.
Do not adjust G_Offset on the other chan-
nels, just record the power. It should be
within the limits listed in the tuning results
file.
Channel Cell PCS
Low 991 25
LowMid 107 200
MidLow 245 400
Mid 384 600
MidHigh 512 800
HighMid 660 1000
High 799 1199*
*1199 not a voice channel, but used in tun-
ing.
TN G_Offset (Cell)
See description of previous tuning. This
step reports G_Offset.
step reports G_Offset.
If G_Offset is not within the limits, trouble-
shoot the Cell TX.
shoot the Cell TX.
TN PA Gain Cal (PCS)
This tuning characterizes the PCS PA
gain curve.
gain curve.
If the power readings are low, check the
AGC voltages. You can also probe on the PA
input to find out if the power level is low
going into the PA, or if the power level is
correct going into the PA but the PA gain is
too low. If the power level going into the PA
is too low, probe the TX chain at all the
other points prior to the PA. When that
point is identified, check the soldering of all
related components, and replace compo-
nents until the fault is found. If the power
on the PA input is not low and the PA AGC
voltage is correct, similarly probe the power
at all points after the PA to find the fault,
being extremely careful not to short the
probing point to ground because this will
instantly destroy the PA. Visually check sol-
dering first, and probe on PA output as a
last resort.
AGC voltages. You can also probe on the PA
input to find out if the power level is low
going into the PA, or if the power level is
correct going into the PA but the PA gain is
too low. If the power level going into the PA
is too low, probe the TX chain at all the
other points prior to the PA. When that
point is identified, check the soldering of all
related components, and replace compo-
nents until the fault is found. If the power
on the PA input is not low and the PA AGC
voltage is correct, similarly probe the power
at all points after the PA to find the fault,
being extremely careful not to short the
probing point to ground because this will
instantly destroy the PA. Visually check sol-
dering first, and probe on PA output as a
last resort.
Tuning Title
Description
Troubleshooting