Tait TM8100 mobiles, Service Manual

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278 Transmitter Fault Finding (>25W) TM8100/TM8200 Service Manual
© Tait Electronics Limited November 2007
11.2 Transmitter RF Power
Introduction
If there is no fault with the power supplies, check the transmitter RF power
and correct any fault. The procedure is covered in the following eight tasks:
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Task 4 : check forward and reverse powers
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Task 5 : check RF output power
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Task 6 : power unchanged regardless of setting
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Task 7 : check for inhibiting of transmitter
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Task 8 : check temperature sensor
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Task 9 : power and current are skewed
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Task 10 : repair output matching circuitry
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Task 11 : power and current are low
The measurement points for diagnosing faults concerning the transmitter
RF power are summarized in
Figure 11.5 . Data required for the first task
(checking the forward and reverse powers) is supplied in Table 11.3 .
Table 11.3 Voltages in millivolts corresponding to nominal forward and reverse powers
Frequency band Forward power (318 command) Reverse power (319 command)
B1 2600 to 3400 < 500
G2 3100 to 3800 < 600
H5 3200 to 3900 < 700
H7 3300 to 4000 < 900
K5 2000 to 2800 < 500