Kenwood NX-3400 Service Manual page 59

5.2 Failure diagnosis of the GPS section
Overview:
When the GPS function does not operate, use this flowchart to determine the problem.
BT/GPS IC (IC351)
When the BT/GPS IC is problematic, it is necessary to replace the printed circuit board by the Service Main unit in service. Various
ESN/default adjustment values are written on the service unit. Please refer to "5.6 Replacing Main Unit".
Major parts for a GPS circuit
• GPS antenna (Connect on CN152, CN153)
• Front End Module (A151)
• SAW Filter (L359)
• BT/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.
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 MAIN UNIT PCB.
IC401
IC352
Level
UART UART
conversion
IC
MPU/DSP
IC
IC353
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.
DISPLAY UNIT
IC351
A151
FEM HPF
BT/GPS
IC
L359
RF
SAW
Matching
Filter
X351
32.768kHz
Clock
MAIN UNIT
(No.RA070<Rev.001>)1-59
SheetMetal
ANT GPS
Matching
ANT
Hyper
ATT
Pogo
CN354
Current
CN356
Monitor
Circuit