Yes, the trailer has tube fuses but only 5 were in use. I hadn't considered loose fuse clips . When I got the trailer, the bakelite base of the fuse block installed had suffered melting from arcing of the DC feed. While exploring I found a new one which PO apparently purchased but didn't install. I labeled all the leads to match the paper label on the chasis, switched out the block, and replaced the leads. The end clips did tend to rotate on the old one; quite tight on the replacement; nonetheless, I would prefer a defect in the
electrical bonding of the fuse clips of one empty circuit to finding a wizard to check out the converter.
jack