Voltage Monitoring - Pioneer DDJ-T1 Service Manual

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5.3 VOLTAGE MONITORING

The MAIN_UCOM of this unit always monitors for power failure of the unit and will shut the unit off immediately after
an error is detected.
Content to be monitored
Any power failure generated inside the Power block on the UCOM_ASSY, such as voltage drop and voltage rise.
Power to be monitored: V+5_D, V+5_A, V+6, V-6, V+3R3_D, V+3R3_UCOM
Microcomputer Detection terminal and its terminal voltage
TP103 (F-DET, TP terminal) or IC701 (MAIN_UCOM) 23-pin FAULT_DET terminal
Normal: 3.3 V
Abnormal: 0 V
Timing of monitoring start
400 msec after the unit is turned ON
Timing upon judgment as a failure
50 msec after an error is detected
LED indication when an error is generated
All LEDs are unlit after an error is generated.
With other models, the Standby LED flashes to notify of a power failure. However, this does not apply to this model,
because a Standby LED is not provided with it.
Restoration method
After the unit shuts itself off because of an error, after completing diagnosis, disconnect the AC adapter and USB cable
and wait at least 1 minute before turning the unit back on.
Diagnostic procedure
1 Disconnect the AC adapter and USB cable.
2 Remove R147 from the UCOM Assy. Note: This step will disable power monitoring.
3 Reconnect the AC adapter and USB cable.
4 As the unit is turned on in a normal way, check each voltage in this state.
Note: Because power will be forcibly supplied even if any voltage is abnormal, if abnormal voltage continues, the defective
point may produce heat, which may be dangerous. Therefore, during diagnosis, be sure to disconnect the AC
adapter and USB cable several seconds after they are connected so that forcible powering will not continue.
5 If the voltage of any power IC is abnormal, the circuit that uses that power or the power IC itself may be defective.
6 Repair the defective part then check that the voltage of the repaired part becomes normal.
7 Return R147 to its original position on the UCOM Assy.
Note: This step will enable power monitoring.
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