Tait TM8100 mobiles Service Manual page 257

Table 10.2 Front-end tuning voltages and corresponding DAC values
Tuning voltages at five different frequencies
Frequency band
FE TUNE0
A4 band
Frequency (MHz) 65.9
DAC value 0 to 40
Voltage (V) 0 to 0.47
B1 band
Frequency (MHz) 135.9
DAC value 37 ± 20
Voltage (V) 0.44 ± 0.24
C0 band
Frequency (MHz) 173.9
DAC value 41 ± 20
Voltage (V) 0.48 ± 0.24
D1 band
Frequency (MHz) 215.9
DAC value 42 ± 20
Voltage (V) 0.5 ± 0.2
H5 band
Frequency (MHz) 399.9
DAC value 0 to 36
Voltage (V) 0 to 0.43
H6 band
Frequency (MHz) 449.9
DAC value 41 ± 20
Voltage (V) 0.48 ± 0.24
TM8100/TM8200 Service Manual
© Tait Electronics Limited November 2007
FE TUNE1
72.1
89 ± 15
1.05 ± 0.18
145.1
88 ± 15
1.04 ± 0.18
187.1
104 ± 15
1.22 ± 0.18
228.1
103 ± 15
1.2 ± 0.18
417.1
94 ± 15
1.11 ± 0.18
470.1
91 ± 15
1.07 ± 0.18
K5 band only:
For the K band, check the circuitry as follows when the sensitivity loss is
moderate. For all other bands, the steps begin
1. Remove the
FE TOP
2. Check the soldering of all the components of the front-end circuitry
from C400 to IC409 (see
3. Check the 3V supply voltage at L420 and L421; use the measurement
points shown in
4. Also check the LNA enable conditions. First measure V
the collector of IC404 or IC405 and ground (see
IC404 is enabled for channels between 850 to 970MHz, and IC405
is enabled for channels between 762 and 776MHz.
V : 2.9±0.1V
c
5. If the checks in
If there is a fault, repair it and go to
FE TUNE2
77.1
134 ± 15
1.58 ± 0.18
155.1
136 ± 15
1.60 ± 0.18
200.1
149 ± 15
1.75 ± 0.18
241.1
151 ± 15
1.7 ± 0.18
435.1
106 ± 15
1.25 ± 0.18
490.1
134 ± 15
1.58 ± 0.18
can and, if not already done, the
Figure 10.1
Figure 10.1.
Step 2 to Step 4 reveal no fault, go to
Step
FE TUNE3 FE TUNE4
82.1 88.1
173 ± 15 218 ± 15
2.04 ± 0.18 2.56 ± 0.18
164.1 174.1
174 ± 15 210 ± 15
2.04 ± 0.18 2.57 ± 0.18
213.1 225.1
187 ± 15 220 ± 15
2.20 ± 0.18 2.59 ± 0.18
253.1 266.1
187 ± 15 224 ± 10
2.2 ± 0.18 2.6 ± 0.12
452.1 470.1
156 ± 15 191 ± 15
1.84 ± 0.18 2.25 ± 0.18
510.1 530.1
176 ± 15 210 ± 15
2.07 ± 0.18 2.47 ± 0.18
on page 256.
can.
IF TOP
and Figure 10.4).
on pin 1 of
c
Figure 10.1).
Step 6.
7.
Receiver Fault Finding 257