It is a bit of a concern--cap's don't just blow willy nilly, but could have happened due to the long storage.
Tantalum capacitors, of this era, DID have a habit of launching like a rocket from a PC board.Dangerous, without safety glasses, when this happens on electronics work bench !
I HOPE one of the regulator pass devices aren't short..
That can be a potential cause. Do you know how to test?
There are a handful of top KWM-380 experts in Cedar Rapids, IA area (Collins HQ, radio was mfg. nearby in Anamosa, IA).
These qualified Collins employees (some in support and design) SHOULD be sought for advice -- this radio is NOT for Novice techs, due to scarcity of some parts and low number of these radios and military HF-380 produced.
Jim Maccani, WØHUP is a very good Collins tech on the KWM-380.
Jim Maccani - WØHUP
4140 Elkhorn Drive N.E.
Cedar Rapids, IA 52411
Hal Guretzky - K6DPZ
95-15 108 Street
Richmond Hill, NY 11419