By "solenoid" he may likely be referring to a bad motor starter relay in the RCM panel. The older RCM panels didn't have fuses, such as this one from Houston, TX for example, which was manufactured in the early 1960s.

However, at some point fuses were added, as seen on this RCM from Norman, OK manufactured in the early to mid 1970s (someone more knowledgeable than myself may be able to chime in with the exact year this change was made).

As for the cause of the blown fuses and bad motor starter, there are any number of possibilities (including a lightning strike) of which that could result. A replacement motor starter relay, wire continuity check, and motor check would likely take care of most issues, but there could be other issues with this particular unit which would have prompted the EMA to consider replacement.
Understandably, the older Thunderbolts like these get, the more municipalities consider age and the difficultly of finding replacement parts a sufficient reason to upgrade to newer systems. It's still sad to see them disappear.