Kenwood NX-3720HG Service Manual page 163

Pass
Verify the BT/GPS control
signal (RXD2).
CN1 (7pin): Square
waveform UART data of 3.3V
logic.
Baud rate:
Default: 115.2kbps
After: 3.967Mbps.
Pass
[The BT/GPS IC is
abnormal]
Replace the PCB.
Check the PCB side B (a).
Pass
[The BT/GPS power supply line 33BT circuit is
faulty]
Verify the PCB side B parts.
C5, C46, C44, C49
Replace any abnormal parts.
Check the PCB side B (b).
Pass
[The BT/GPS power supply line 18BT circuit is
faulty]
Verify the PCB side A parts.
C2, C47, L5, L13, C45, C48
Replace any abnormal parts.
Verify the BT/GPS control
Fail
signal (18BT_HCI_TX).
IC6 (8pin):
Square waveform UART data
of 1.8V logic.
[The RXD2 (18BT_HCI_TX)
line circuit is faulty]
Verify the CP1, IC6, R22
Replace any abnormal parts.
Fail
Fail
Fail
Pass
[The BT/GPS IC is
abnormal]
Replace the PCB.
[The BT/GPS IC is
abnormal]
Replace the PCB.
Check the TX-RX UNIT
PCB.
(No.RA054<Rev.001>)1-163