TM8100/TM8200 Service Manual Power Supply Fault Finding 163
© Tait Electronics Limited June 2006
7 Power Supply Fault Finding
Fault-Diagnosis
Task s
Fault diagnosis of the power-supply circuitry is divided into the following
tasks:
■ Task 1: check inputs to SMPS
■ Task 2: check 3.3V supply
■ Task 3: check linear regulators (for 2.5V, 3V, 6V and 9V supplies)
■ Task 4: check power-up configuration
■ Task 5: check power-up options
■ Task 6: check provision of external power.
Types of Fault Which of the above tasks are applicable depends on the nature of the fault:
■ Radio fails to power up: The radio fails to power up immediately when
power is applied, or it fails to power up when power is applied and the
ON/OFF key is pressed. Carry out Task 1 to Task 3
■ Power-up option has failed: The radio powers up when the ON/OFF key is
pressed, but not for a power-up option for which it is configured.
Carry out Task 4 and Task 5.
■ External power at connector has failed: The external power required at
a particular connector is no longer present. Carry out Task 6.
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