HP LaserJet 5L Service Manual - Page 57

AC Power Distribution, DC Power Distribution, Overcurrent/Overvoltage Protection, SleepMode

Page 57 highlights

Power System (on DC Controller PCA) The AC, DC, and high voltage power supply circuits are all contained within the DC Controller PCA. AC Power Distribution The AC power circuitry supplies AC voltage whenever the power cord is connected to the AC power source. AC voltage is distributed to the DC power supply circuitry and to the AC driver circuitry, which controls AC voltage to the fusing assembly's heating element. DC Power Distribution The DC power distribution circuitry, located on the DC Controller PCA, distributes +5 V DC and +12 V DC as follows: +5 V DC: Formatter PCA Photosensors DC Controller Circuitry Laser/Beam Detect Circuitry +12 V DC: +12VA DC: Motor Scanner Motor Solenoid High Voltage Power Supply Overcurrent/Overvoltage Protection There are two overvoltage /overcurrent devices in this printer: • Fuse F101 provides overcurrent protection for the fusing system circuitry. To check or replace the fuse requires the removal of the DC Controller. Fuse 102 (found only on 110V units) provides overcurrent protection to the printer DC power supply circuitry. • In addition, the +12V DC and +5V DC power circuitry contains an overcurrent protection circuit which automatically shuts off the output voltage when an overcurrent condition occurs due to a short or abnormal voltage on the load side. SleepMode Instead of a power switch, the printer has a SleepMode function. After the printer has been idle for 15 minutes, it turns itself off by shifting to SleepMode. The front panel lights remain off, and the printer retains all printer settings and downloaded fonts and macros while in SleepMode. 5 - 6 Functional Overview

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Power System (on DC Controller PCA)
The AC, DC, and high voltage power supply circuits are all contained within the DC
Controller PCA.
AC Power Distribution
The AC power circuitry supplies AC voltage whenever the power cord is connected
to the AC power source. AC voltage is distributed to the DC power supply circuitry
and to the AC driver circuitry, which controls AC voltage to the fusing assembly’s
heating element.
DC Power Distribution
The DC power distribution circuitry, located on the DC Controller PCA, distributes
+5 V DC and +12 V DC as follows:
+5 V DC:
Formatter PCA
Photosensors
DC Controller Circuitry
Laser/Beam Detect Circuitry
+12 V DC:
Motor
Scanner Motor
Solenoid
+12VA DC:
High Voltage Power Supply
Overcurrent/Overvoltage Protection
There are two overvoltage /overcurrent
devices in this printer:
Fuse F101 provides overcurrent protection for the fusing system circuitry.
To
check or replace the fuse requires the removal of the DC Controller. Fuse 102
(found only on 110V units) provides overcurrent protection to the printer DC power
supply circuitry.
In addition, the +12V DC and +5V DC power circuitry contains an overcurrent
protection circuit which automatically shuts off the output voltage when an
overcurrent condition occurs due to a short or abnormal voltage on the load side.
SleepMode
Instead of a power switch, the printer has a SleepMode function. After the printer
has been idle for 15 minutes, it turns itself off by shifting to SleepMode. The front
panel lights remain off, and the printer retains all printer settings and downloaded
fonts and macros while in SleepMode.
5 - 6
Functional Overview