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Service Guide ML520/521
Chapter 2 Principles of Operation
2.1.08 Power Supply Circuit
The switching type power supply circuit supplies the +5 vdc, +/-8 vdc, 10 VAC and +40 vdc.
Voltage/Signal
Purpose
+5 vdc
IC logic levels, LED drive voltages
+8 vdc
Serial interface line voltage, comparator IC
+10 VAC
Serial interface line voltage and the printhead analog circuit
+40 vdc
Printhead, space motor and line feed motor drive voltage
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