Kenwood NX-5400 Service Manual page 70

When a normal
condition is confirmed.
Verify the reference clock for the BT/GPS.
(BT_CLK) Intersection of
C850 and R861:
Sine waveform, 19.2MHz, 0.2 to 1.2 Vp-p
When a normal
condition is confirmed.
Verify the BT/GPS control
signal (18BT_HCI_RX).
IC852 (8pin):
Square waveform UART data
of 1.8V logic.
Baud rate:
Default: 115.2kbps
After: 3.967Mbps.
When a normal
condition is confirmed.
Verify the BT/GPS control
signal (RXD2).
CP851 (1 pin):
Square waveform UART data of
3.3V logic.
Baud rate:
Default: 115.2kbps
After: 3.967Mbps.
When a normal
condition is confirmed.
Check the PCB side B.
Check the PCB side B.
When a normal
condition is confirmed.
Verify the RTC for the BT/GPS.
X850 (3 pin):
Square waveform, 32.768kHz, 1.8Vp-p
When a normal
condition is confirmed.
[The BT/GPS IC is abnormal]
Replace the PCB.
1-70 (No.RA016<Rev.001>)
[The reference clock circuit
When an abnormal
for the BT/GPS is faulty]
condition is confirmed.
Verify the PCB side A parts
C850, R861, R862.
Replace any abnormal parts.
Verify the BT/GPS control
When an abnormal
signal (TXD2).
condition is confirmed.
CP851 (2 pin):
Square waveform UART data of
3.3V logic.
[The 18BT_HCI_RX (TXD2)
line circuit is faulty]
Verify the CP851, IC852, R858
Replace any abnormal parts
When an abnormal
Verify the BT/GPS control
condition is confirmed.
signal (18BT_HCI_TX).
IC852 (8 pin):
Square waveform UART data
of 1.8V logic.
[The RXD2 (18BT_HCI_TX)
line circuit is faulty]
Verify the CP851, IC852, R858
Replace any abnormal parts.
When an abnormal
condition is confirmed.
Verify the RTC line circuit for the BT/GPS.
X850, L854, C875
Replace any abnormal parts.
When an abnormal
condition is confirmed.
When an abnormal
condition is confirmed.
When a normal
condition is confirmed.
When an abnormal
condition is confirmed.
When a normal
condition is confirmed.
Check the PCB side B (c).
[MPU/DSP (IC702) is faulty]
Replace the PCB.
[BT/GPS IC (IC850) is faulty]
Replace the PCB.