Tait TM8000 Series

20 TMAA01-01 Line-Interface Board TM8000 Mobile Radio Accessories Manual
March 2004 © Tait Electronics Limited
3. Disassemble the radio in order to gain access to the options cavity. For
detailed disassembly instructions, refer to the disassembly procedure
in the TM8100 Service Manual.
Connect the internal options loom between SK2 on the line-inter-
face board and SK102 on the radio’s main PCB.
4. Set up the test equipment shown in Figure 2.1 , and follow the adjustment
procedure for RV1, RV2 and RV3 described in the following section.
2.2.4 Adjusting RV1, RV2 and RV3
Setting the Keying
Time Delay (RV1)
The keying time delay circuit is used to prevent the burst of noise occurring
before a mobile is able to mute the audio when the carrier signal disappears.
The keying time delay is used in conjuction with the keying signal
(SK1 pin 1).
Set DIP8 off, and adjust RV1 for the required time delay. Rotate RV1
clockwise to increase the delay, and counterclockwise to reduce the delay.
Setting the Line
Output Level (RV2)
Monitor the line output (SK1 pins 14 and 15) and apply an on-channel
signal from the RF signal generator at an output level of -47dBm,
modulated to 60% of system deviation, at 1kHz AF.
Adjust the RV2 for a line output level of -10dBm.
Setting the Line
Input Level (RV3)
Apply a line input signal of -10dBm and key the transmitter.
■ For a two-wire configuration, apply the line input signal to pins 14 and
15 on SK1.
■ For a four-wire configuration, apply the line input signal to pins 4 and
10 on SK1.
Adjust RV3 until 60% of system deviation at 1kHz is achieved.