168
Power Supply Fault Finding
TM8100/TM8200 Service Manual
© Tait Electronics Limited
June 2006
Task 3 —
Check Linear
Regulators
This task describes the general procedure for checking any linear regulator.
There are two possible faults: either the regulator has failed and prevents the
radio from powering up, or the regulator voltage is incorrect. (The regulator
IC might or might not have been removed during earlier checks.)
1.
Disconnect the 13.8 V supply. Check for continuity and shorts to
ground (if not already done) on the input, output and control line of
the relevant regulator IC. Repair any fault.
2.
If the regulator IC has been removed, resolder it in position.
3.
Reconnect the 13.8 V supply and press the
ON
/
OFF
key. If the radio
powers up or the correct regulator voltage is restored, return to
. If the repair failed, go to
.
4.
Disconnect the 13.8 V supply. Replace the regulator IC with a spare.
Reconnect the 13.8 V supply and press the
ON
/
OFF
key. If the radio
powers up or the correct regulator voltage is restored, go to
. If the repair failed, replace the board and go to
Figure 7.3
Power-supply circuitry under the
CDC BOT
can, including 3V regulator IC603 and 2.5V
regulator IC604
LO2 BOT CAN
CAN FOR
DIGITAL
BOARD
TP601
Summary of Contents for TM8235
Page 1: ...TM8100 mobiles TM8200 mobiles Service Manual MMA 00005 04 Issue 4 June 2006...
Page 10: ...10 TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 62: ...62 Description TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 148: ...148 Disassembly and Reassembly TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 162: ...162 Servicing Procedures TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 178: ...178 Interface Fault Finding TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 258: ...258 Receiver Fault Finding TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 446: ...446 Spare Parts TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...