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Grey ATX power supply unit with single fan and multiple cables

Replace Power

Replace Power RPSU-C99-54 420W ATX power supply

SKU CH-T4SJ-4E5WZ MPN RPSU-C99-54

A 420 W ATX unit with 20+4 pin, 12 V, SATA, Molex and floppy leads plus a switchable 110/220 V input and an 80 mm fan

  • ColorGrey
  • TypeATX
  • Fans1
  • Weight0.1
  • 420W output powers demanding desktop upgrades
  • Switchable 110V or 220V input suits global mains voltages
  • 80mm fan cools the unit during sustained loads
  • 20+4 pin ATX plus 12V ATX connectors fit most motherboards
  • SATA and Molex leads support drives and peripherals

Replacement ATX power supply

This 420W ATX unit replaces Bestec ATX-300-420W, ATX-300-12Z Rev.BD and ATX-250-12Z models. It fits HP, Dell, Compaq and other common desktop systems that need a direct swap. The grey enclosure uses a single fan for airflow. It is built for upgrades and custom builds where the original supply has failed.

Thermals noise and power draw

An 80mm fan provides cooling while the unit delivers up to 420W. Input voltage is switchable between 110V and 220V. The supply runs from a standard wall outlet without extra wiring. Normal desktop loads stay within the rated output.

Connector mix and upgrade scope

Cables include one 15-inch SATA connector, one 14-inch 20+4 pin ATX connector, one 14-inch 12V ATX connector, two 15-inch large peripheral connectors, two 6-inch large peripheral connectors and one 6-inch small peripheral connector. This covers Molex, SATA and floppy devices. The jump is worth it when the old supply cannot power added drives or a newer motherboard. Buyers who need more total wattage or modular cables should look elsewhere.

Highlights

  • 420W output powers demanding desktop upgrades
  • Switchable 110V or 220V input suits global mains voltages
  • 80mm fan cools the unit during sustained loads
  • 20+4 pin ATX plus 12V ATX connectors fit most motherboards
  • SATA and Molex leads support drives and peripherals

Specifications

BrandReplace Power
ModelRPSU-C99-54
ColorGrey
TypeATX
Fans1
Weight0.1

Questions about this item

How do I install the 20+4 pin ATX connector, and what is the common mistake?

Align the 20+4 pin ATX connector with the motherboard socket and press firmly until the latch clicks; the step people miss is leaving the extra four pins unseated on a 24-pin board.

What maintenance or replacement will the 80mm fan need later?

The 80mm fan should be cleared of dust every six to twelve months; if bearing noise appears or airflow drops, replace the entire unit as the fan is not user-serviceable.

What limit appears first under sustained 420W load?

The 110V/220V switchable input and single 80mm fan mean thermal headroom is the first limit; prolonged full-load operation will trigger over-temperature protection before any voltage rail drops.

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