Kenwood NX-3400 Service Manual page 65

Pass
Verify the BT/GPS control
signal (RXD2).
CP352 (1pin): Square
waveform UART data of 3.2V
logic.
Baud rate:
Default: 115.2kbps
After: 3.967Mbps.
Pass
Verify the BT/GPS control
signal (/BT_SHUTDOWN).
R353: 1.8V
Pass
Verify the RTC for the BT/GPS.
X351 (3pin): Square waveform, 32.768 kHz,
1.8Vp-p
Pass
[The BT/GPS IC is
abnormal]
Replace the PCB.
 Descriptions of signal names
(1) 32BT: BT/GPS IC 3.2V power supply
(2) 18BT: BT/GPS IC 1.8V power supply
(3) TXD2: BT/GPS serial data line connected to UART TX of MPU/DSP IC (MPU/DSP to BT/GPS IC)
(4) RXD2: BT/GPS serial data line connected to UART RX of MPU/DSP IC (MPU/DSP to BT/GPS IC)
(5) 18BT_HCI_RX: BT/GPS serial data line connected to UART RX of BT/GPS IC (MPU to BT/GPS IC)
(6) 18BT_HCI_TX: BT/GPS serial data line connected to UART TX of GPS IC (BT/GPS IC to MPU)
(7) /BT_SHUTDOWN: BT/GPS active control of MPU/DSP IC (MPU/DSP to BT/GPS IC) High  Active, Low  Reset
Verify the BT/GPS control
Fail
signal (18BT_HCI_TX).
IC352 (8pin):
Square waveform UART data
of 1.8V logic.
[The RXD2 (18BT_HCI_TX)
line circuit is faulty]
Verify the CP352, IC352.
Replace any abnormal parts.
[The /BT_SHUTDOWN line
circuit is faulty]
Fail
Verify the R353, Q351.
Replace any abnormal parts.
Fail
Fail
Pass
Fail
Verify the RTC line circuit for the BT/GPS.
X351, L358, C375
Replace any abnormal parts.
[BT/GPS IC (IC351) is
faulty]
Replace the PCB.
[MPU/DSP (IC401) is
faulty]
Replace the PCB.
(No.RA070<Rev.001>)1-65