Hytera MD78X Service Manual page 621

VHF (136-174MHz 50W) Information Service Manual
Description of Normal Situations:
[1] During sensitivity test, use a communication test set to demodulate the audio signal (TP4012 and
TP4016). If the signal is demodulated normally, it is concluded that the front panel is defective.
[2] Use the communication test set to input a 44.85MHz IF signal at the mixer, and see whether it can
be processed normally afterwards.
[3] Use a spectrum analyzer to check whether TP704 can output the second LO signal (47.1MHz).
[4] Use the communication test set to apply an RF signal of -100dBm, and test the sensitivity.
[5] Use a spectrum analyzer to test the LO signal received by TP6106. If its strength is about 18dBm,
go to check the mixer; otherwise, check the VCO.
[6] Use the communication test set to apply an RF signal of -110dBm at TP6104, and test the
sensitivity.
[7] Use the communication test set to apply an RF signal of -110dBm at TP6103, and test the
sensitivity.
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