I had some of those old Haughtons with the 24VDC locks. Every couple of months I was in the hatch cleaning door locks, and making sure they were perfect, after the mysterious, intermittant EME trips started happening. They were a real drag.

It Don't mean a thing if it aint got that swing.

Cool, Free, Johnny Smith courtesy of NPR..HERE
http://www.npr.org/ramfiles/asc/asc25.smith.asx