Hi Dave,
The early units were susceptible to damage from inrush current (overcurrent) since they were not protected by thermistors or other current limiting devices. Whether or not they actually suffered damage was due to a combination of factors; such as the total active load plugged into the unit at turn-on combined with the actual wall voltage supplied by the local utility (above 124 VAC could be a problem.)
Further, if you have one of these early EP units, DO NOT plug an SP-15A (balanced power unit) into it, even though the literature implies that it's not only OK, but desirable to do so. You will fry the main board of the EP. In fact I'd go further and advise owners not to do this regardless of their EP's vintage ;-)