Kenwood NX-3720HG Service Manual page 158

Pass
Verify the BT/GPS control
signal
(BTFM_nSHUTDoWN).
IC1 (5pin): 1.8V
Pass
Verify the BT/GPS control
signal (18BT_RX).
IC6 (7pin):
Square waveform UART data
of 1.8V logic.
Baud rate:
Default: 115.2kbps
After: 3.967Mbps.
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.
1-158 (No.RA054<Rev.001>)
Verify the BT/GPS control
Fail
signal (/BT_SHUTDOWN).
CN1 (14pin): 3.3V
[/BT_SHUTDOWN line circuit
is faulty]
Verify the IC1, R7
Replace any abnormal parts.
Verify the BT/GPS control
signal (TXD2).
CN1 (6pin):
Fail
Square waveform UART data
of 3.3V logic.
[The 18BT_HCI_RX (TXD2)
line circuit is faulty]
Verify the CP1, IC6, R22
Replace any abnormal parts.
Verify the BT/GPS control
signal (18BT_HCI_TX).
Fail
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
Pass
Fail
Pass
Fail
Pass
Check the TX-RX UNIT
PCB
Check the TX-RX UNIT
PCB
Check the TX-RX UNIT
PCB