Kenwood NX-3720HG Service Manual page 157

Check the BT/GPS UNIT PCB side A.
Pass
Verify the BT/GPS power
supply.
(33BT) L4: 3.3V
Pass
Verify the BT/GPS power
supply.
(18BT) L5: 1.8V
Pass
Verify the RTC for the
Fail
BT/GPS.
X2 (3 pin): Square waveform,
32.768 kHz, 1.8Vp-p
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 BT/GPS power
Fail
supply.
(33GPS) L6: 3.3V
Verify the RF input circuit for the GPS.
SAW, GPS IC RF Matching
From connecter to SAW: CN5, C40, R24, R23
SAW parts: L9, D17, D18
GPS IC RF Matching parts: C38, C36, L7
[The BT/GPS power supply
Fail
line 33BT circuit is faulty]
Verify the PCB side A parts.
L4, C15, C19, C20, C33
Replace any abnormal parts.
[The BT/GPS power supply
Fail
line 18BT circuit is faulty]
Verify the PCB side A parts.
C18, C13, C31, L8, C39
Replace any abnormal parts.
Verify the RTC line circuit for
the BT/GPS.
X2, L8, C39
Replace any abnormal parts.
[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.
Verify the power supply voltage
after removing the KRA-40.
(33GPS) L6:3.3V
[The BT/GPS power supply
line 33GPS circuit is faulty]
C7, C23, C24, R15, C25, R16,
R19, C26, C27, C29, L2, R14,
C3
Replace any abnormal parts.
Fail
Fail
Fail
Pass
Fail
Fail
[The GPS RF input circuit is faulty]
Replace the GPS RF input circuit
parts. (only the parts which can be
replaced) If any unexchangeable
parts are abnormal, replace the PCB.
Check the BT/GPS UNIT
PCB side B (a).
Check the BT/GPS UNIT
PCB side B (b).
[The KRA-40 may be
broken]
Replace the KRA-40
[The BT/GPS IC is
abnormal]
Replace the PCB.
(No.RA054<Rev.001>)1-157