
144
Interface Fault Finding
TP9100 Service Manual
© Tait Electronics Limited
May 2005
Task 6 —
Status LED Faulty
Use this procedure if the status LED is not operating according to
. For example, the red LED does not operate when
the radio is transmitting, or the green LED does not operate when the radio
is receiving. Before proceeding make sure the fault is not transmitter or
receiver related. See
“Check the Transmit and Transmit-Audio Functions”
and
“Check the Receive and Receive-Audio Functions” on
If the status LED is faulty:
1.
Remove the front panel and the main shield assembly.
2.
Connect a multimeter or oscilloscope to pin A1 (green LED) or pin
A2 (red LED) of
DS900
. See
3.
Activate the relevant LED. For the green LED, feed a signal without
modulation on the receive channel. For the red LED, ensure the
antenna port is terminated with a 50
Ω
load or antenna, and
temporarily place the radio in transmit mode.
Important
Do not transmit for more than five seconds with the main
board removed from the chassis.
4.
As the LED is activated, monitor the voltage on the appropriate pin.
The voltage should be as follows:
5.
If the voltage levels are not correct proceed to
. If they are
6.
Replace
Q904
, and
R932
(red LED faulty) and/or
R935
(green LED
faulty). Retest the LED. If the LED is still faulty, proceed to
7.
Replace
DS900
, and
R921
(red LED faulty) and/or
R920
(green
LED faulty). Retest the LED.
8.
If the LED is still faulty, replace the main board.
green LED: pin A1
red LED: pin A2
LED inactive: <1V
LED active: >3V
Summary of Contents for TP9100
Page 1: ...TP9100 portables Service Manual MPA 00005 01 Issue 1 00 May 2005 ...
Page 4: ...4 TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 10: ...10 TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 74: ...74 Circuit Descriptions TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 78: ...78 TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 100: ...100 General Information TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 126: ...126 Disassembly and Reassembly TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 148: ...148 Interface Fault Finding TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 158: ...158 Power Supply Fault Finding TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 250: ...250 Transmitter Fault Finding TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 268: ...268 Receiver Fault Finding TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 294: ...294 Spare Parts TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 298: ...298 Antenna Identification Chart TP9100 Service Manual Tait Electronics Limited May 2005 ...