Key Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | DIGITAL POWER |
| Part Numbers | CPCI-AC-6U-500, 900-7002-99 |
| Form Factor | 6U CompactPCI front-pluggable module |
| Input Voltage | 90–264 VAC, 47–63 Hz, active PFC |
| Total Output Power | 500 W continuous (multi-rail) |
| Output Rails | +5 V, +3.3 V, +12 V, –12 V, +5 VSB |
| Backplane Interface | PICMG 2.11 CompactPCI power interface; 47-pin P47 connector typical |
| Management Signals | DC OK/FAIL, Inhibit/Enable, Remote Sense; I²C/SMBus on many builds |
| Protections | OVP, OCP, SCP, over-temperature protection |
| Cooling | Internal forced-air fan with guided airflow |
| Operating Temperature | Typically 0 °C to +50 °C at rated load; verify with OEM datasheet |
| Status | Legacy/obsolete spare |
Product Introduction
I have replaced enough cPCI power modules in cramped telecom and industrial racks to know this: the power supply is the first thing blamed when a chassis behaves strangely, and the last thing people check until the fans stop spinning. The DIGITAL POWER CPCI-AC-6U-500, part number 900-7002-99, is a 6U CompactPCI AC power supply that feeds the usual cPCI rails — +5 V, +3.3 V, ±12 V, and +5 VSB — through a PICMG-compliant backplane interface.Engineers keep this module in the spares bin because it handles universal AC input, active PFC, and hot-swap insertion without requiring a full chassis shutdown. At 500 W, it can support dense CPU blades, I/O cards, and legacy cPCI processor slots, provided airflow and minimum-load rules are respected. I would not treat it as a generic 500 W brick. The P47 pinout, remote-sense wiring, inhibit logic, and fan direction must match the chassis. One wrong assumption there, and the module powers up fine while the backplane sees garbage.
Quality SOP & Tech Pitfalls
The Lab Report (SOP)
- Visual and counterfeit check: Verify DIGITAL POWER label, 900-7002-99 marking, revision code, and P47 connector condition.
- Mechanical inspection: Check front-panel alignment, extractor handles, fan grille, and mounting hardware.
- Insulation and continuity: Use a Fluke 115 or equivalent to check AC input, chassis ground, and P47 pin continuity against the OEM pinout.
- Live test on cPCI test rack: Apply 90–264 VAC and verify +5 V, +3.3 V, +12 V, –12 V, and +5 VSB within tolerance.
- Signal validation: Confirm DC OK/FAIL, Inhibit/Enable, Remote Sense, and any I²C/SMBus responses.
- Load step check: Verify regulation under light and rated load; watch for overshoot on +3.3 V and +5 V.
- ESD sealing: Anti-static bag, desiccant, rigid box, and photo documentation of label and test results.
The Engineer’s Warning (Pitfalls)
- Minimum-load failure. Many cPCI supplies need a minimum load on +5 V to stay regulated. I have seen a chassis reboot randomly because the new supply was tested with no load, then installed into a lightly loaded slot.
- Remote-sense wiring errors. If remote sense is left floating or tied incorrectly, the rails can drift high enough to nuisance-trip other cards.
- Fan airflow direction mismatch. The module may push or pull air differently than the chassis expects. In a sealed rack, that turns a 500 W supply into a thermal bottleneck within weeks.
- Revision and pinout drift. 900-7002-99 may have multiple hardware revisions. Do not assume P47 signals, inhibit polarity, or current-share pins are identical across builds.
Installation & Configuration Guide
1. Pre-Installation ⚠️
- Follow site LOTO procedures.
- Disconnect AC mains and wait for bus capacitors to discharge.
- Photograph the installed module label, P47 connector, fan orientation, and chassis airflow arrows.
2. Removal
- Disable the supply if the chassis supports inhibit control.
- Release extractor handles.
- Slide the module out without forcing the P47 connector.
- Inspect the backplane P47 socket for bent pins before installing the replacement.
3. Installation
- Verify the replacement part number, revision, and fan direction match the original.
- Ensure extractor handles are fully open before insertion.
- Seat the module evenly; do not hammer it in.
- Close extractor handles to lock the P47 connector.
4. Power-On & Testing
- Restore AC power.
- Verify fan spin-up and normal noise profile.
- Measure +5 V, +3.3 V, +12 V, –12 V, and +5 VSB at the backplane or test points.
- Confirm DC OK/FAIL and inhibit signals match chassis expectations.
- Monitor temperatures for at least 30 minutes under normal load.
- Log the serial number and revision in the maintenance record.
Compatible Replacement Models
- ✅ CPCI-AC-6U-500 → CPCI-AC-6U-500 (same revision): Drop-in replacement if the 900-7002-99 revision, P47 pinout, fan direction, and rail ratings match.
- ⚠️ CPCI-AC-6U-500 → Kontron cPCI 6U AC 500W: Same 6U cPCI 500 W class and PICMG 2.11 interface, but requires verification of P47 pinout, minimum load, remote sense, inhibit logic, and mechanical fit before deployment.
- ❌ CPCI-AC-6U-500 → Non-PICMG 2.11 power supply: Hardware modification required. Do not attempt unless redesigning the chassis and accepting full integration risk.
Frequently Asked Questions (FAQ)
Can I hot-swap this supply?
Yes, the CPCI-AC-6U-500 is described as hot-swap capable, but only if the chassis, backplane, and site procedures allow it. I still prefer a planned maintenance window. Hot-swapping a 500 W AC supply is not the moment to discover a bad P47 socket.Is 900-7002-99 the same as CPCI-AC-6U-500?
They are commonly listed together as the same product family. Treat them as related, but confirm the label, revision, and pinout before installation. Distributor listings are not a substitute for an OEM datasheet.Why does one source say 751 W?
Some public pages list 751 W, while most list 500 W continuous. That mismatch is exactly why you must photograph the nameplate and verify the rated output before putting it into service.Does it support N+1 redundancy?
Many cPCI 500 W modules support redundancy and current sharing, but this depends on the specific build and chassis. Do not assume current-share or OR-ing behavior without confirming the P47 signals.What fails first on these modules?
Fans, input fuses, and P47 connector wear. The electronics often survive longer than the mechanical parts. If the fan sounds rough, replace it before it takes down the chassis.Can I use this in a 3U cPCI chassis?
No. This is a 6U module. It will not fit a 3U slot mechanically, and the backplane pinout may differ.
