Hytera PD362, Service Manual

Page: 101 / 141

Troubleshooting Flow Chart
Uc (430
‐
470 MHz)
26
Description of Normal Situations:
[1] Output voltage by Q6004 Pin 3 is about 3V.
[2] Output voltage by U306 Pin 5 or input voltage by Q6004 Pin 4 is about 3V.
[3] Check the collector voltage and base voltage of Q6005 when the circuit is not receiving signals. Normally, the
voltage is about 0.754 V at pole B, about 2.728 V at pole C and 0 V at pole E.
[4] Check the collector voltage and base voltage of Q6006 when the circuit is not receiving signals. Normally, the
voltage is about 0.754 V at pole B, about 2.25V at pole C and 0 V at pole E.
[5] Cut off the front-end circuit, and input a 38.85 MHz IF signal (with modulation signal) at C6094 to test
IF sensitivity. Normally, the IF sensitivity is -109dBm.
[6] Frequency of Q611 is 38.4 MHz (output by C697).
[7] Frequency output by 2NDLO_1 is 19.2 MHz.
[8] Input a -40dBm RF signal at the antenna connector and test at R6047. Normally, gain is higher than
10 dB and output signal is stronge r than - 3 0 dBm.
[9] Test at C6093 (the post-stage circuit has not been cut off). Normally, the frequency is -38.85 MHz
(current channel frequency) with amplitude of about 5 dBm.
[10] Test at D502 (the post-stage circuit has not been cut off). Normally, the frequency is -38.85 MHz
(current channel frequency) with amplitude of about 0 dBm.
[11] Frequency output by mixer is 38.85 MHz.
[12] The input signal in the antenna port is -47 dBm with standard tuning information (AF=1 kHz
，
FM=3 kHz).
6.3
Transmitter Circuit
Caution
The following tests must be operated with a power supply of 3.7 V.