TM8100/TM8200 Service Manual Fault Finding of Control Head with 1- 2- or 3-Digit Display 429
© Tait Electronics Limited June 2006
15 Fault Finding of Control Head with
1- 2- or 3-Digit Display
Overview This section describes the fault finding of the control head with 1-, 2- or 3-
digit display for the following faults:
■ display faulty but not LEDs
■ some LEDs faulty
■ all LEDs faulty
■ display and all LEDs faulty
■ some but not all keys faulty
■ all keys faulty
■ speaker faulty
■ volume control faulty
The faults can be detected by visual inspection (refer to “Check the
User Interface” on page 153).
General The following applies for all fault finding procedures:
Important Do not disconnect or connect the control head while
power is supplied to the radio.
■ If the radio does not switch on when power is supplied, the radio may
be programmed to go into the status it was in when powered down.
Connect a known good control head, power up the radio, and change
the relevant setting in the programming application. Remember to
program the original setting before returning the radio to the customer.
■ For disassembly and re-assembly instructions, refer to “Disassembling
and Reassembling the Control Head” on page 141.
■ If the repair fails or no fault could be found, replace the control-head
board.
■ After completing the repair, carry out the tasks in “Initial Tasks” on
page 149.