Kenwood NX-3720HG Service Manual page 156

5.2 Failure diagnosis of the GPS section (GPS model only)
Overview:
When the GPS function does not operate, use this flowchart to determine the problem.
Major parts for a GPS circuit
• GPS active antenna: KRA-40 (option)
• Coaxial cable: E0E-0003-00
• SAW Filter (L9)
• Bluetooth/GPS IC (IC5)
• Level conversion IC (IC6, IC7)
• TCXO 19.2MHz (X1)
• 32.768 kHz clock (X2)
• 33BT Regulator (IC3)
• 18BT Regulator (IC2)
• 33GPS Regulator (IC4)
• MPU/DSP IC (IC404)
Positioning is not carried out normally.
When the power supply is turned ON,
"GPS ANT FAIL" is displayed
Not displayed
Verify the connection of KRA-40.
(SMA connector)
Pass
Verify the connection of the SMA
connecting cable.
CN5 – E0E-0003-00
Pass
Check the BT/GPS UNIT PCB side A.
1-156 (No.RA054<Rev.001>)
IC404
UART
UART
MPU/DSP
IC
PCM
PCM
TX-RX UNIT
Displayed
Fail
Connect the KRA-40
correctly.
Fail
Connect the cable to
the CN5 correctly.
IC6 IC5
Level
UART
RF
Conversion
Matching
IC
BT/GPS
IC7
IC
PCM
Bias
Level
Conversion
IC
X1 X2
TCXO 32.768KHz
Clock
19.2MHz
Power is not supplied to the KRA-40.
Verify the connection of KRA-40.
Fail
(SMA connector)
Verify the connection of the SMA
Fail
connecting cable.
CN5 – E0E-0003-00
Check the BT/GPS UNIT PCB side B.
L9 GPS Antenna unit
SAW GPS
Filter Antenna
Coaxial
cable
CN5
BT/GPS UNIT
Pass
Pass