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Silver rectangular ATX power supply unit with single fan and 20+4 pin connector visible

Replace Power

Replace Power RPSU-ATX-250-12Z 420W ATX power supply

SKU CH-S9BE-QAEJQ MPN RPSU-ATX-250-12Z

A 420W ATX power supply with reduced depth, built-in 20+4 pin adapter, and multiple protection features for legacy system replacements

  • TypeATX
  • Fans1
  • Weight1.5
  • Replaces multiple legacy HP and eMachine units with 420W output
  • Built-in 20+4 pin connector supports both 24 and 20 pin motherboards
  • Reduced depth design at 5.9 x 3.4 x 4 inches fits tight chassis
  • Comprehensive protection includes over current, over power, over voltage and short circuit
  • Switchable 110-260V AC input works worldwide

Replacement for HP and Bestec units

This 420 watt ATX power supply replaces several legacy Bestec and HP models including the ATX-250-12Z and ATX-300-12Z series. It fits HP Compaq and eMachine systems that originally used lower wattage units. The reduced depth design helps it sit inside compact chassis where standard depth units cannot.

Upgrade from 250W and 300W originals

Moving from a 250 watt or 300 watt factory supply to this 420 watt unit adds headroom for extra drives or a modest graphics card. The jump is worth it when the original unit has failed or when added components exceed the old supply's combined rail limits. Built-in over current, over power, over voltage and short circuit protection guards the new hardware.

Fits tight builds with 20+4 pin flexibility

A built-in 20+4 pin adapter lets the same cable serve both 24 pin and 20 pin motherboards. Connectors include one P4 12V four pin, three SATA 15 pin, three LP4 four pin and one floppy four pin. Input voltage switches between 110 and 260 volts AC at 50 or 60 Hz. Output rails deliver 3.3V at 11A, 5V at 12A, dual 12V rails at 8A each, -12V at 0.3A and 5VSB at 2A.

Highlights

  • Replaces multiple legacy HP and eMachine units with 420W output
  • Built-in 20+4 pin connector supports both 24 and 20 pin motherboards
  • Reduced depth design at 5.9 x 3.4 x 4 inches fits tight chassis
  • Comprehensive protection includes over current, over power, over voltage and short circuit
  • Switchable 110-260V AC input works worldwide

Specifications

BrandReplace Power
ModelRPSU-ATX-250-12Z
TypeATX
Fans1
Weight1.5

Questions about this item

Will the 5.9" width and 3.4" height fit my HP case that used the Bestec ATX-250-12Z?

Yes, the reduced depth of 4" and the 5.9" x 3.4" footprint match the original Bestec ATX-250-12Z form factor for direct replacement in compatible HP Compaq cases.

How do I connect the 20+4 pin ATX connector to my older 20-pin motherboard?

The built-in 20+4 pin adapter splits so the extra 4 pins detach; plug only the 20-pin portion into the board and leave the 4-pin section unconnected.

When should I replace the single internal fan?

Replace the fan if bearing noise appears or airflow drops enough to let internal temperatures exceed the 50 °C full-load operating limit.

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