Power Supply Dell 240W SFF EPA HF (Model HNJC4-RFB) — 240W small form factor internal PSU

Dell 240W SFF EPA HF (Model HNJC4-RFB) — 240W small form factor internal PSU is a compact internal power supply designed for compatible Dell small form factor desktops and workstations. The unit provides up to 240 watts of DC output with EPA high-efficiency operation and HF (high-frequency) filtering to reduce electromagnetic interference. Intended as a direct replacement or upgrade for existing SFF power modules, the Dell HNJC4-RFB restores reliable power delivery and helps maintain system stability in space-constrained systems.

Advantages

The Dell 240W SFF EPA HF (HNJC4-RFB) offers a balanced combination of power density and energy efficiency. EPA high-efficiency operation reduces power loss and can contribute to lower operating costs in continuous-use environments. HF filtering reduces electrical noise that can affect sensitive components, and the small form factor design enables installation in compact chassis without major modification. This unit follows Dell compatibility and mounting standards for straightforward replacement in supported models.

Suitable for

• Replacing a faulty or aging SFF power supply in compatible Dell small form factor desktops
• Upgrading an existing SFF PSU to restore full 240W capacity for workstation-class components
• Compact office PCs, point-of-sale systems, and space-limited workstations requiring a reliable internal PSU
• Environments where reduced electromagnetic interference is desired due to HF filtering

Key specifications

• Manufacturer: Dell
• Model / MPN: HNJC4-RFB
• EAN: 5715063002940
• Output power: 240W maximum
• Form factor: Small Form Factor (SFF) internal PSU
• Features: EPA high-efficiency operation, HF filtering for reduced interference
• Application: Compatible Dell SFF desktops and workstations (check chassis compatibility)

How to use

Power off the computer and disconnect all external power and peripherals before beginning. Open the SFF chassis following the system manufacturer’s service instructions. Remove the failed or original SFF power supply by disconnecting internal power cables and any retaining screws or brackets. Install the Dell 240W SFF EPA HF (HNJC4-RFB) in the same orientation, secure with the original mounting hardware, and reconnect the internal power connectors to the motherboard and drives. Close the chassis, reconnect external power, and perform a power-on and system check to confirm proper operation.

Usage recommendations

Verify chassis and connector compatibility with your Dell system model before purchase. Use only Dell-recommended installation procedures and anti-static precautions when handling the PSU. For systems that draw near the 240W limit, confirm the combined power requirements of installed components to ensure adequate headroom. If uncertain about installation, consult Dell technical documentation or a qualified technician.