Rx Circuit - Hytera PT580 Service Manual

RX Circuit

Abnormal reception
Test TP5001 and
TP5002 to check
whether the I/Q signal is
normal. [12]
Yes
Check whether
I/Q signal is output
via the baseband.
Check the power
No
No
supply for the receiver
and whether U6501
outputs 3V voltage.
Yes
Check whether the RF LO and IF
LO of the receiver work normally
No
and whether normal stable
voltage is available at L1001 and
L1004. [1]
Yes
Check whether the amplitude
of the signal at Pin5 of U4103
is normal. [2]
Yes
Check whether the amplitude
No
of the signal at Pin1 of U410 is
normal. [3]
Yes
Check whether the amplitude
No
of the input signal at Pin1 of
U5001 is normal. [4]
Yes
Check whether the
No
amplitude of the output
signal at U5001 is
normal. [5]
Yes
No
Check whether U5002 outputs
73.35MHz IF signal. [7]
Yes
Check whether the
No
amplitude of the output
signal at Z5003 is
normal. [9]
Yes
Check whether the
No
amplitude of the output
signal at Q5001 is
normal. [10]
Yes
Test TP5001 and TP5002 to check
No
whether normal I/Q signal is
availablel. [12]
Yes
Completed
Replace U6501.
Yes
Check whether 3.3V input
No
voltage is available at Pin1
of U6501 and 3.3V enable
signal is available at Pin3.
Check the FGU.
No Check whether the antenna
connector or duplexer is inappropriately
soldered or damaged.
Replace U4103.
Check whether Z5001/D5001
/C5001 is inappropriately soldered or
damaged.
Yes
Check whether Pin3/Pin4
of U5001 is supplied
No
normally. [6]
No
Check whether Pin4
of U5002 is supplied
Yes
normally. [8]
Check the Z5003 match circuit to see
whether Z5003 is soldered inappropriately. If
not, please replace Z5003.
No
Check whether the voltage for
Pin2/Pin3 of Q5001 is normal.
Yes
[11]
Check whether 3V voltage is
supplied to Pin2/Pin20 of U5005,
and whether 146.7MHz IF LO
signal is available at Pin1/Pin28.
25
Service Manual
Check the
enable signal and
power supply via the
baseband.
Replace U5001.
Check whether normal RF
LO signal is available at Pin3
of U5002. [13]
Check whether the 3.3V RX voltage is
normal. If yes, please replace U5003.
Replace
Q5001.
No
Yes
Replace U5005.