Xerox DocuColor 12/DCCS50, Service Manual

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10-14 DocuColor 12/DCCS50
Power Switching Control Circuitry
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Principles of Operation
Power Switching Control Circuitry
As shown in Figure 1 , power switching control uses circuitry on the AC Driver PWBA with
inputs from other assemblies. Machine power can only be switched on by toggling the Main
Power Switch. When pressed, this switch energizes the Set Coil of Power Relay 1, which ener-
gizes Power Relay 2 and causes Switched AC Power to be supplied by the AC Driver PWBA.
AC power can be switched off by any of three events:
• The operator toggles the Main Power Switch.
• The IOT CPU PWBA asserts the Main Power Off line. This only occurs due to abnormal
execution of CPU firmware. When the operator again toggles the Main Power Switch, the
entire machine, including the IOT CPU, is rebooted.
• The IOT CPU PWBA asserts the Power Off line. This places the machine in to Sleep
Mode and is done as a power saving technique.
Each of these inputs activates the Reset Coil of Power Relay 1, deenergizing the relay and
releasing Power Relay 2. This removes Switched AC Power from the machine.
The machine saves power in two stages. The first transition is from Ready Mode to Low Power
Mode. This occurs 15 minutes (default time) after the machine operation initiated by the user.
This delay period is stored in IOT NVM and can be adjusted over a range of 1 to 240 minutes.
When in Low Power Mode, the fuser heaters are off.
The second transition is to Sleep Mode. The default delay is 60 minutes after the transition to
Low Power Mode. The delay value is also stored in IOT NVM and can be adjusted over a range
of 15 to 240 minutes.
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