Over-Current/Over-Voltage/Overload Protection; Safety Interruption; Power Supply Voltage Detection; Table 1-4 Low Voltage Power Supply Dc Power Specifications - HP LaserJet Enterprise 700 M712 series Handbuch Zur Fehlerbehebung

Table 1-4 Low voltage power supply DC power specifications (continued)
DC voltage
+5V +5V
+3.3V +3.3VA
+3.3VB
+3.3VC
+3.3VD

Over-current/over-voltage/overload protection

The over-current/overvoltage protection automatically stops the DC voltage to the product components
whenever an excessive current or abnormal voltage is detected. The overload protection automatically
stops the DC voltage to the product components whenever the temperature of the low-voltage power
supply PCA rises to specified degrees.
The low-voltage power supply has a protective circuit against over-current, over-voltage and overload to
prevent failures in the power supply circuit. If DC voltage is not being supplied from the low-voltage
power supply, the protective function might be running. In this case, turn the power off and unplug the
power cord. Do not turn the product switch on until the root cause is found and corrected.
The DC controller determines a low-voltage power supply failure and notifies the formatter when the
protective function runs.
In addition, the low-voltage power supply has three fuses to protect against over-current. If over-current
flows into the AC line, the fuse blows to stop AC power.

Safety interruption

For user and service technician's safety, the product interrupts the power supply of +24V by turning off
the interlock switch. The DC power to the following components is interrupted:
High-voltage power supply
●
Fuser motor
●
The remote switch control circuit turns on or off the product so that the AC power flows even the power
switch is turned off. Be sure to unplug the power cord before disassembling the product.

Power supply voltage detection

The power supply voltage detection controls the fuser properly according to the voltage. The DC
controller detects whether the low-voltage power supply voltage is 100V or 220V according to the
POWER SUPPLY VOLTAGE signal (/PSTYP100).
ENWW
Behavior
Off during Sleep mode (sleep level1, active off and inactive off)
Constantly supplied
Off during Sleep mode (inactive off)
Off during Sleep mode (active off and inactive off)
Off during Sleep mode (sleep level1, active off and inactive off)
Engine control system
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