Failure Diagnosis Of The Gps Section - Kenwood NX-3220 K Service Manual

5.2

Failure diagnosis of the GPS section

Overview:
When the GPS function does not operate, use this flowchart to determine the problem.
Major parts for a GPS circuit
• GPS antenna (Connect on CN152, CN153)
• Front End Module (A151)
• SAW Filter (L359)
• Bluetooth/GPS IC (IC351)
• Level conversion IC (IC352, IC353)
• TCXO 19.2MHz (X401)
• 32.768 kHz clock (X351)
• 32BT Regulator (IC8)
• 18BT Regulator (IC7)
• MPU/DSP IC (IC401)
Positioning is not carried out normally.
Are you operating at a location that is suitable for
receiving the GPS signals?
Pass
Verify the contact of the GPS internal antenna with
the PCB.
Pass
Check the DISPLAY UNIT PCB.
Check the DISPLAY UNIT PCB.
Pass
Verify the ANT Matching Parts.
Visually check to C172, L173.
Pass
Verify the High Pass Filter Parts. Verify
the C175, L176, C177, L178, C179, D180
and D181.
Pass
Verify the FEM.
Verify the L187, C184, C186, R189 and
C190. Check the voltage of the C192 with
the side CN157. And verify PCB side B
parts L194, C193 and R191.
Pass
Check the TX-RX UNIT PCB.
IC401
IC352
Level
UART UART
conversion
IC
MPU/DSP
IC353
IC
Level
PCM
PCM
Conversion
IC
X401
TCXO
19.2MHz
Fail
Operate at place where is good visibility of the sky.
Fail
Re-assembling the GPS antenna correctly
If an antenna is defective, replace the GPS internal antenna.
Fail
Replace any abnormal parts.
Fail
Replace any abnormal parts.
Fail
Replace any abnormal parts.
DISPLAYUNIT
IC351
A151
FEM HPF
BT/GPS
IC
L359
RF
SAW
Matching
Filter
X351
32.768KHz
Clock
TX-RX UNIT
(No.RA053<Rev.001>)1-151
SheetMetal
ANT GPS
Matching
ANT
Hyper
ATT
Pogo
CN354
Current
Monitor CN356
Circuit