Pioneer DDJ-T1 Service Manual page 24

1
A
No. Cause/Symptom Point to be checked
UCOM Assy
Power failure 1
4-1
FAULT_DET
UCOM Assy
FAULT_DET
Power failure 2
B
CDCB
4-2
Identification of
DJMB
defective Assy
UCOM Assy
FAULT_DET
Power failure 3
CDCB
4-3 Identification of
DJMB
defective Assy
C
Power failure 4
UCOM Assy
UCOM Assy
4-4
FAULT_DET
Identification of
defective Assy
D
[1-2] Failure in the microcomputer system
No. Cause/Symptom Point to be checked
Power failure in
1 UCOM Assy
the MAIN_UCOM
MAIN_UCOM
2 UCOM Assy
Reset circuit
error
E
MAIN_UCOM
3 UCOM Assy
X'tal error
MAIN_UCOM
4 UCOM Assy
startup error
F
24
1
2
Item to be checked
Check if the voltage monitoring circuit was
activated:
Turn the unit ON then check the voltages
shown below.
V+5_D:
FAULT_DET, R147 (0 Ω) :
Identify the Assy on which a voltage error
was generated.
Remove all cables other than the cable for
CDJB
CN1004 (USBB to UCOM) from the UCOM
Assy.
JACB
Turn the unit ON then check the V+5_D
HPJK
voltage.
MICB
V+5_D:
FAULT_DET, R147 (0 Ω):
With all cables other than the cable for
CDJB
CN1004 (USBB to UCOM) disconnected
from the UCOM_ASSY, identify the defective
Assy by connecting each connector on the
JACB
UCOM Assy one by one for voltage checks.
HPJK
MICB
Deactivate the voltage monitoring circuit
then check the section with improper
voltage.
Item to be checked
Check if a voltage error was detected.
Check the power terminal of the
MAIN_UCOM (IC701).
Check the Reset terminal (Pin 17) of the
MAIN_UCOM (IC701). (High/Low)
Check the oscillation waveforms of the
X'tal (X701).
After startup, check the lighting statuses of
the LEDs.
(For example, although some of the LEDs
light properly, the unit is not started up
properly.)
2
3
How to distinguish a defective point and/or corrective action
Turn the unit ON then check the voltages shown below.
V+5_D: 2 V or less (abnormal voltage), 4.5 V or higher
(normal voltage)
FAULT_DET, R147(0 Ω): 0 V (abnormal voltage detection),
3.3 V (normal voltage)
In a case of abnormal voltage detection, see [4–2] Power
failure 2.
In a case of normal voltage, poor control over the
microcomputer system may be suspected.
Remove all cables other than the cable for CN1004 (USBB
to UCOM) from the UCOM Assy.
Turn the unit ON then check the V+5_D voltage.
V+5_D: 4.5 V or higher (normal)
FAULT_DET, R147(0 Ω): 3.3 V normal, no detection of a
voltage error)
In a case of normal voltage, see [4–3] Abnormal voltage
detection 3.
In a case of abnormal voltage detection, see [4-4] Power
failure, UCOM Assy.
Identify the defective ASSY, by connecting each connector
on the UCOM Assy, as shown below, one by one for
voltage checks:
CDJ1B: CN905, CN906
CDJ2B: CN903, CN904
CDCB: CN901, CN902
DJMB: CN1001, 1002
JACB: CN302, CN501
HPJK: CN301
MICB: CN303
Repair the defective part of the defective Assy.
If further identification of defective Assys is required, see
the notes in "5.3 Voltage Monitoring" before proceeding to
further diagnostics.
The voltage monitoring circuit can be deactivated by
removing R147 (0 Ω) on the FAULT_DET.
See the notes in "5.3 Voltage Monitoring" before
proceeding to further diagnostics.
To identify the section with improper voltage, check
the voltage at each point on the UCOM Assy.
How to distinguish a defective point and/or corrective action
If the detected voltage error is confirmed, check conduction
between the power supply and GND.
Check the power line and the parts, such as coils (beads),
resistors, and capacitors.
If no problem was found with the parts, power line, and
conduction between the power supply and GND, the
MAIN_UCOM (IC701) may be defective.
In normal operation, the voltage of the Reset terminal
(Pin 17) is high.
If the voltage of the Reset terminal is low, check the power
line, resistors, capacitors, and the Reset IC (IC106).
If the voltage level remains low after the Reset IC (IC106)
is replaced, the MAIN_UCOM (IC701) may be defective.
Check the waveforms of the X'tal (X701).
If an error is found, check the power line, resistors, and
capacitors.
If the waveform remains abnormal after the X'tal (X701) is
replaced, the MAIN_UCOM (IC701) may be defective.
Refer to "[4] Error Indications" in the 6. Service Mode.
If there is no corresponding error indication, reload the
program via USB.
If the normal status is not recovered after all above steps
are performed, the MAIN_UCOM (IC701) may be
defective.
DDJ-T1
3
4
Reference
4.3 POWER
SUPPLY BLOCK
DIAGRAM
5.3 VOLTAGE
MONITORING
10.17 WAVEFORMS
Abnormal voltage
detection
k, p
4.1 OVERALL
CONNECTION
DIAGRAM
4.3 POWER
SUPPLY BLOCK
10.17 WAVEFORMS
Abnormal voltage
detection
k, p
4.1 OVERALL
CONNECTION
DIAGRAM
4.3 POWER
SUPPLY BLOCK
5.3 VOLTAGE
MONITORING
4.3 POWER
SUPPLY BLOCK
5.3 VOLTAGE
MONITORING
Reference
Abnormal
Voltage Detection
10.17 WAVEFORMS
MAIN UCOM
start up
10.17 WAVEFORMS
MAIN UCOM
start up
i
10.17 WAVEFORMS
MAIN UCOM
start up
j
6. Service Mode
[4]
Error Indications
4