Pioneer DDJ-T1 Service Manual page 25

5
No. Cause/Symptom Point to be checked
Power failure in
5 UCOM Assy
the USB_UCOM
USB_UCOM
6 Reset circuit UCOM Assy
error
USB_UCOM
UCOM Assy
7
X'tal error
USB_UCOM
8 I2C communica- UCOM Assy
tion error
EEPROM error
9 UCOM Assy
[2] Display (LED indicators)
[2-1] Any one of the LEDs does not light.
No. Cause/Symptom Point to be checked
1 Defective LED LERelated point
[2-2] Several LEDs do not light.
No. Cause/Symptom Point to be checked
UCOM Assy
CDJ1B
1 Signal errors
CDJ2B
DJMB
2 Defective LEDs Related point
Defective
3 Related point
transistors
[3] Operations (Buttons/VRs/Sliders/NeedleSearch/JOG)
Operation of all buttons, variable controls, and the JOG dial can be confirmed in Service mode.
[3-1] The push buttons are disabled.
No. Cause/Symptom Point to be checked
Loose connection
or defective
1 Related point
switches
Defective MAIN_
2 UCOM Assy
UCOM (IC701)
5
6
Item to be checked
Check if a voltage error was detected.
Check the power terminal of the
USB_UCOM (IC202).
Check the Reset terminal (Pin 10) of the
USB_UCOM (IC202). (High/Low)
Check the oscillation waveforms of the
X'tal (X201).
Check the I2C communication waveforms of the
EEPROM (IC201) immediately after startup.
Reload the program via USB.
Item to be checked
Check the connections of the LED then
check the forward voltage (approx. 2.2 V)
between both ends of the LED.
Item to be checked
Check for any loose connections between
the MAIN_UCOM (IC701) and the LEDs.
Check also that the control signal for the
LEDs is output.
Check the forward voltage (approx. 2.2 V)
between both ends of the LEDs.
Check the transistors.
Item to be checked
Check for any loose connections on the
signal line from the switch to GRID_IC
(IC702), KEY_BUFFER (IC1101, 1102),
and main microcomputer (IC701).
If the symptom persists after the above
corrections.
DDJ-T1
6
7
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 USB_
UCOM (IC202) may be defective.
In normal operation, the voltage of the Reset terminal
(Pin 10) is high.
If the voltage level at the Reset terminal is low, check for
abnormal voltage detection, and check the power line,
resistors, and capacitors. If no problem was found with the
above circuit, parts, and power line, and if the voltage level
is low, the USB_UCOM (IC202) or the MAIN_UCOM
(IC701) may be defective.
If an error is found, check the power line, resistors, and
capacitors.
If the waveform remains abnormal after the X'tal (X201) is
replaced, the USB_UCOM (IC202) may be defective.
Data of the EEPROM (IC201) are loaded only during
startup.
If an error is generated, check the power supply to the
EEPROM, resistors, capacitors, and SW IC (IC203) on the
communication line.
If no problem is found with the power supply, communica-
tion line, and parts, the EEPROM (IC201) or USB_UCOM
(IC202) may be defective.
If no problem is found with the communication waveform in
[8] above, reload the program via USB.
If reloading is successfully performed, the USB_UCOM
(IC202) may be defective.
If reloading fails, the EEPROM (IC201) may be defective.
How to distinguish a defective point and/or corrective action
If the forward voltage is abnormal, the LED may be
defective.
How to distinguish a defective point and/or corrective action
If the control signal is not output, check the
mounting status of the MAIN_UCOM (IC701).
If it is properly mounted, then the IC701 itself may
be defective.
If the forward voltage is abnormal, the LEDs may be
defective.
The transistors may be defective.
How to distinguish a defective point and/or corrective action
If other SWs connected to the same signal line
function properly and if the connections are properly
made, the SW may be defective.
Go to [7-1] Basic Operation Check of the
Microcomputer.
7
8
A
Reference
Abnormal
Voltage Detection
10.17 WAVEFORMS
USB UCOM
start up
Abnormal
Voltage Detection
10.17 WAVEFORMS
USB UCOM
start up
c
B
10.17 WAVEFORMS
USB UCOM
start up
d
10.17 WAVEFORMS
I2C USB UCOM
EEPROM
C
8.4 COPYING THE
PROGRAM FOR THE
USB CONTROLLER
Reference
LED waveform
10.SCHEMATIC
DIAGRAM
D
Reference
Basic Operation
Check of the
MAIN_UCOM
LED waveform
10.SCHEMATIC
DIAGRAM
10.SCHEMATIC
DIAGRAM
E
Reference
Each Signal
Levels
Basic Operation
Check of the
F
MAIN_UCOM
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