Kenwood NX-3400 Service Manual page 61

Verify the reference clock for
the BT/GPS.
Fail
(BT_CLK) Intersection of
R360 and R361: Sine
waveform, 19.2MHz, 0.2 to
1.2 Vp-p
Pass
Verify the BT/GPS control
signal (18BT_RX).
Fail
IC352 (7pin):
Square waveform UART data
of 1.8V logic.
Baud rate:
Default: 115.2kbps
After: 3.967Mbps.
Pass
Verify the BT/GPS control
Fail
signal (RXD2).
CP352 (1pin): Square
waveform UART data of 3.2V
logic.
Baud rate:
Default: 115.2kbps
After: 3.967Mbps.
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.
[The reference clock circuit
for the BT/GPS is faulty]
Verify the PCB side A parts
C356, R360, R861.
Replace any abnormal parts.
Verify the BT/GPS control
signal (TXD2).
Fail
CP352 (2pin):
Square waveform UART data
of 3.2V logic.
Pass
[The 18BT_HCI_RX (TXD2)
line circuit is faulty]
Verify the CP352, IC352 and
R357.
Replace any abnormal parts.
Verify the BT/GPS control
signal (18BT_TX). Fail
IC352 (8pin):
Square waveform UART data
of 1.8V logic.
Pass
[The RXD2 (18BT_TX) line
circuit is faulty]
Verify the CP352, IC352,
R357.
Replace any abnormal parts.
Verify the RTC line circuit for the BT/GPS.
Fail
X351, L358, C375
Replace any abnormal parts.
Check the PCB
Fail
side B (c).
[MPU/DSP (IC401) is
faulty]
Replace the PCB.
[BT/GPS IC (IC351) is
faulty]
Replace the PCB.
(No.RA070<Rev.001>)1-61