If your server does not power on, the cause of the problem might be:
The AC power cords are the direct connection between the server power supplies and the power sources. The server power supplies need separate stable AC circuits. Insufficient voltage levels or fluctuations in power can cause server power problems. The power supplies are designed to operate at a particular voltage and within an acceptable range of voltage fluctuations (see Server Specifications in Sun Server X4-8 Installation Guide).
Action: Check that the AC power cords are connected to the server. Check that the correct power is present at the outlets and monitor the power to verify that it is within the acceptable range. You can verify sufficient AC power by checking the green AC OK indicators next to the AC inlets on the back of the server. When the indicators are lit, the AC power to the server is sufficient. An amber indicator indicates that the AC power is insufficient. You can also verify proper connection and operation by checking the PSU indicator panels, which are located at the front of the server on the PSUs. Lit green AC OK and DC OK indicators show a properly functioning PSU. An amber AC OK indicator indicates that the AC power to the PSU is insufficient.
Prevention: Use the AC power cord retaining clips and position the cords to minimize the risk of accidental disconnection. Ensure that the AC circuits that supply power to the server are stable and not overburdened.
The server power supplies (PSUs) provide the necessary server voltages from the AC power outlets. If the PSUs are inoperable, unplugged, or disengaged from the internal connectors, the server cannot power on.
Action: Check that the AC cables are connected to both PSUs. Check that the PSUs are operational (the PSU indicator panel should have a lit green AC OK indicator). Ensure that the PSU is properly installed. A PSU that is not fully engaged with its internal connector does not have power applied and does not have a lit green AC OK indicator.
Prevention: When a power supply fails, replace it immediately. When installing a power supply, ensure that it is fully seated and engaged with its connector inside the drive bay. A properly installed PSU, has a lit green AC OK indicator.