User's Manual Part 5
* 123)
2 Switch on the MOX (Manually Operated Transmit) PTT and check that the modu-
lation is at approximately 60% of full system deviation. Check that no audio path
is evident through the normal microphone.
Activate the PTT on the normal microphone and check that there is now an audio
path through the microphone.
3 With no audio, adjust RV67 for 0.8V at TP5.
Remove the TCXO PCB to operate the /IN-LOCK signal and check that the DC
level now goes to 6.5V ±0.5V. Replace the TCXO.
4 Increase the audio level by 10dB.
With all PTTs off, activate the
or
keys (radio is in VOX
mode).
Sweep the audio generator slowly from 1kHz to 100Hz and back again and check
that the transmitter keys between 700Hz ±70Hz and 250Hz ±25Hz.
When going from receive to transmit the radio should key instantly at these cut-
offs. When going from transmit to receive check there is a delay of approximately
1.5 seconds.
Check that VOX transmit is inhibited if the channel is busy (assuming LINK4B is
fitted).
5 Switch on the MOX PTT and set the audio generator to 1kHz at a level of -50dBm
(3mV).
Monitor TP9 and check that the level on the scope is 1.2Vp-p ±0.2V.
Increase the audio level by 10dB and check that the level on the scope is about the
same.
Decrease audio level by 20dB. After observing the charging action of the compres-
sor, the level on the scope should be 0.4Vp-p ±0.1V.
Trunking only: The audio at TP9 should be there on an assigned channel, a
non-trunked channel or in test mode. When the radio is on a control channel or
hunting for a control channel, the audio should be muted.
6 A final system check can be done with the directional microphone and footswitch.
Fn