Kenwood NX-3720HG Service Manual page 162

Pass
Verify the reference clock for
the BT/GPS.
(BT_CLK) Intersection of C8
and C9: Sine waveform,
19.2MHz, 0.2 to 1.2 Vp-p
Pass
Check the BT/GPS UNIT PCB side B.
Check the BT/GPS UNIT PCB side B.
Pass
Verify the ANT Matching
Parts.
Visually check to R27, R29
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
1-162 (No.RA054<Rev.001>)
[The reference clock circuit
for the BT/GPS is faulty]
Fail
Verify the R9, Q1, R10, R26,
R12, R13, X1, C4, C8, C9
Replace any abnormal parts.
Fail
Replace any abnormal parts.
Verify the BT/GPS control
signal (/BT_SHUTDOWN).
Fail
CN1 (16pin): 3.3V
[/BT_SHUTDOWN line circuit
is faulty]
Verify the IC1, R7
Replace any abnormal parts.
Verify the BT/GPS control
signal (TXD2).
Fail
CN1 (6pin):
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.
Fail
Pass
Fail
Pass
Check the TX-RX UNIT
PCB.
Check the TX-RX UNIT
PCB.