ALAN Electronics Tectalk FM PMR 446, Service Manual

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d) Setting of Squelch sensitivity
1) Set the standard channel.
2) In squelch mode, SQ volume RV1 must be turned counterclockwise.
3) After adjusting SSG to channel frequency, the adjusting SSG to
level. –120dBm set is audio on, -130dBm set is audio off.
4.5 RECEIVER TEST
a) Audio Distortion Test
1) SSG should be adjusted like way of point b) and RF level sets to
-47dBm.
2) Adjust to 0.7Vrms(8 Ohms load) seeing Audio wave.
3) Read the needle of distortion meter(normal condition would be
less than 5% distortion.)
b) Rx sensitivity test
SSG should be adjusted to 20dB of SINAD's point needle seeing wave
of oscilloscope as SSG sets in 1kHz with 1.5KHz frequency deviation.
At this time, normal RF level is < -118dBm.
c) Squelch Test
After RF level of SSG should be set to the least level, RF level
should be gradually increased until speaker makes audio sound.
At this point, check RF level (Check Audio on : -120dBm,
Audio off : -130dBm)
4.6 Symptoms, Check point & Correction
a) Diagnose method
1) Check each switch to work well.
2) Check voltage of battery.
3) Problem develops from transmitter or receiver?
b) Troubleshooting
1) Transmitter
Power key is on condition but does not work.
Battery could completely discharge.
Battery cell twist..
Touch problem come between Battery and Radio.
Fail to transmit
Run out of battery or charge problem.
Fault of PTT key.
Fault of Q4, Q5.
Transmitter works but frequency is unmatched
Out of order in frequency synthesizer.
Out of order in X-tal(X2).
Audio does not sound(Tx power and Tx frequency are normal)
Problem of microphone or MIC connector.
IC U7 problem.
Tx is set when switch is on.
Tx switch problem