[ LEGACY AND PROPRIETARY OEM SUPPLIES // IDENTIFIED UNIT ]
OptiPlex 390 SFF 240 W power supply
Exact platform-and-assembly record for Dell L240AS-00 used in the Dell OptiPlex 390 Small Form Factor (SFF). Confirm the entire label, spare/FRU number and revision: similar host names can ship with electrically different supplies.
SAFETY: Never open a PSU or probe its interior. Hazardous voltage can remain after unplugging. Disconnect mains before service and replace the complete unit unless service is performed by a qualified technician.
Recorded model specifications
| Exact model / FRU | Dell assembly identifier L240AS-00; verify all suffixes, spare number, revision and nameplate on the unit. |
|---|---|
| Host-system compatibility | Dell OptiPlex 390 Small Form Factor (SFF) only when the system-board revision, machine type, chassis form and documented service configuration match. This is not a generic replacement PSU. |
| Form and rated output | OEM proprietary internal supply; rated total output class: 240 W. Per-rail/combined limits and continuous-load derating must be checked on the exact PSU label/service documentation. |
| AC input | 100–240 V AC, 4.0–2.0 A, 50/60 Hz; confirm unit nameplate. |
| DC output rails | +3.3 V, +5 V, +12 V, −12 V and +5 V standby; total output is 240 W. Per-rail currents and combined limits are label/revision-specific. |
| Connectors / pinout warning | Dell keyed motherboard and CPU harnesses; do not treat this connector as standard ATX. A physically fitting plug does not prove electrical compatibility; never reuse unrelated modular cables or rely on an unverified adapter. |
| Mechanical envelope | Approx. 82 × 65 × 175 mm (width × height × depth); verify this assembly’s mounting envelope. Use the platform manual to check tabs, screws, airflow direction, fan clearance and cable reach; do not force-fit. |
| Electrical/revision caveat | The PSU rating label controls rail-current, combined-power, standby, protection and input details for the exact unit. A host service manual establishes supported platform replacement; it does not make the assembly an ATX standard supply. |
Service and compatibility notes
- Use only the documented Dell OptiPlex 390 Small Form Factor (SFF) replacement assembly or a manufacturer-authorized superseding part number verified against the actual machine type.
- Confirm keyed motherboard/CPU/GPU connectors and pin assignments from the Dell service manual before replacement. Do not assume ATX, EPS or PCIe pinouts from connector shape.
- Dimensions are nominal identification guidance. Confirm the exact part's labels, mounting geometry, vents and harness orientation before purchase or installation.
- Follow the OEM manual's shutdown, mains-disconnect and chassis service steps. Never open or electrically probe the PSU.
Sources & further reading
- Dell OptiPlex 390 service manual — PSU removal and installationOfficial Dell service/manual source for the named host platform. Use the exact machine type and assembly suffix when checking fit, replacement procedure and revisions.
- Dell OptiPlex 390 manuals and technical documentsOfficial Dell service/manual source for the named host platform. Use the exact machine type and assembly suffix when checking fit, replacement procedure and revisions.
Manufacturer documentation is authoritative for platform-level service and supported assemblies. Confirm electrical input/output data and dimensions against the individual unit’s nameplate and the manual revision matching its exact SKU.