Replace Power
Replace Power 420W ATX power supply for HP A376x A384x A387x A400n A400y A404x A405n A406x
A 420 watt ATX power supply with reduced depth for HP desktops, offering 24-pin, 4-pin, SATA and Molex connectors
- ColorGrey
- TypeATX
- Fans1
- Weight4
- Fits tight cases with a 5.86-inch depth
- 420-watt peak output supports demanding components
- 24-pin and 4-pin connectors power motherboard and CPU
- Three SATA and two Molex plugs run drives and peripherals
- 110/220-volt input works worldwide
Replacement 420W ATX for HP Desktops
This unit replaces the original power supply in HP A376x, A384x, A387x, A400n, A400y, A404x, A405n and A406x systems. It fits a standard ATX slot with a reduced depth of 5.86 inches for tighter chassis clearance. The grey housing holds a single 80mm fan and ships new. Builders restoring these specific HP models will find the connector set matches the factory layout.
Sustained Load Behaviour
The label states a max wattage of 420 watts and a total continuous wattage of 280 watts. Hold-up time is rated at a minimum of 17 ms at nominal input, while rise time stays below 70 ms. Low ripple and noise are specified across the +5V, -5V, +12V1, +12V2, +3.3V, -12V and +5V-SB rails. AC input covers 110/220V at 47 to 63 Hz for global mains compatibility.
Upgrade Context
This supply replaces a failed or noisy OEM unit in the listed HP desktops without requiring adapter cables. The fixed cabling provides one 24 (20+4) pin motherboard connector, one 4-pin CPU connector, three SATA 15-pin connectors, two Molex 4-pin connectors and one floppy 4-pin connector. It does not suit builds needing PCIe power cables, higher continuous wattage or modular cabling.
Highlights
- Fits tight cases with a 5.86-inch depth
- 420-watt peak output supports demanding components
- 24-pin and 4-pin connectors power motherboard and CPU
- Three SATA and two Molex plugs run drives and peripherals
- 110/220-volt input works worldwide
Specifications
| Brand | Replace Power |
|---|---|
| Model | HP A376x A384x A387x A400n A400y A404x A405n A406x |
| Color | Grey |
| Type | ATX |
| Fans | 1 |
| Weight | 4 |
Questions about this item
How loud is the 80 mm fan when this 420 W supply runs continuously?
The 80 mm fan provides stable cooling for long-life performance while the unit maintains low ripple and noise under load.
Which connectors must my system already provide for this unit to work?
It requires a standard ATX motherboard socket for the 20+4 pin connector and a 4-pin CPU power header; all SATA, Molex and floppy leads are built into the supply.
Will the reduced 5.86 in depth fit the HP A376x, A384x, A387x, A400n, A400y, A404x, A405n and A406x chassis I still use?
Yes, the shorter 5.86 inch depth is designed for increased compatibility with those HP models and standard ATX slots.
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