Transmitter Fault Finding (>25W) - Tait TM8100 mobiles Service Manual

11 Transmitter Fault Finding (>25W)
Introduction
>25W
Fault-Diagnosis
Tasks
CCTM Commands
TM8100/TM8200 Service Manual
© Tait Electronics Limited November 2007
This section covers the diagnosis of faults in the 40W/50W and 30W/35W
transmitter circuitry. The main indication of a fault in the transmitter is a
reduction in range. This implies that the power output is wrong or too low.
Another type of fault is exhibited when the radio always transmits at full
power, even if set otherwise. Regardless of the fault, the lock status should
be normal.
The procedure for diagnosing transmitter faults is divided into tasks, which
are grouped into the following sections:
"Power Supplies"
■
"Transmitter RF Power"
■
"Biasing of PA Driver and PAs"
■
"RF Signal Path".
■
Before beginning the fault diagnosis with
following information regarding CCTM commands, frequency bands, can
removal and replacement, and transmit tests.
The CCTM commands required in this section are listed in
Full details of the commands are given in
Mode (CCTM)" on page
"Power
"Computer-Controlled Test
123.
Transmitter Fault Finding (>25W)
Supplies", note the
Table 11.1.
267