The DIGITAL Personal Workstation a/au-Series system operates in an ambient temperature range of 10 to 40C. The system unit is cooled by three fans: one in the upper front for the CPU, one in the lower front for the expansion cards, and one in the power supply.
The power supply contains a fan-fail detector that shuts down power after a 1-second delay if its internal fan fails. The two front fans are attached to the riser card.
Intermittent problems could result from overheating. Check that the air flow path is clear. Make sure there are no materials blocking the input grill. Also check to see that the cables inside the system are properly dressed. A dangling cable will impede airflow to the system.