02/20006-75DocuPrint N2025/N2825 GP 5.19General Procedures / InformationInitial IssueGP 5.19 Power SupplyLVPS (Low Voltage Power Supply) Figure 1The N2025/N2825 LVPS is a separately-excited, feedforward switching regulator. The LVPSproduces +24 VDC, +5 VDC, and +5 VDC (B) voltages from AC power. +5 VDC (B) is labeledas 5V-LD in the printer wiring diagrams.The LVPS has the following three protections.-Short-circuit protection (over current protection)When the 5VDC or 24VCD supply circuit is short-circuited, and an excessive current begins toflow in the circuit, all DC supplies are shut down. To reset this short-circuit protection, switch offprinter power, remove the cause, then switch on printer power two or three minutes after turn-ing the power off.-Open-circuit protection (overvoltage protection)When the 5VDC or 24VDC supply circuit is open or the connector is disconnected, the outputvoltage of the circuit begins to decrease after about 1 minute and the output is stopped. Toreset this open-circuit protection, switch off the printer power, reconnect the connector or repairthe open circuit, then switch on printer power about five minutes after the power off.-Low-voltage protectionWhen the voltage of the 24VDC supply circuit becomes 15 VDC or lower, the output voltage ofthe 24VDC supply circuit begins to decrease and the output is stopped.HVPS (High Voltage Power Supply) Figure 1The HVPS produces the high voltages applied to the BCR, BTR, DB, and DTS from +24 VDCsupplied by the LVPS under the control of the Print Engine Controller PWB.The HVPS has an overcurrent protection. If an excessive current begins to flow in any of thehigh voltage output circuits, all high voltages are shut down. To reset the protection circuit afteran overcurrent shutdown, switch off the printer power, remove the cause, then switch on theprinter power again.Figure 1 HVPS/LVPS Locations
