Pilot controlled lighting controller

Very long shot, I know, but - does anyone have any schematic or any
documentation whatsoever on a pilot controller runway light controller,
Model BX-2, made by Subil Enterprises, Inc., Des Moine, IA 50317? Can't
find any current address or phone number for that company. Unit was likely
made in the late '70s-early '80s. Problem is very low sensitivity. Has
worked fine until recently. Obviously very difficult to troubleshoot
without any info.

Thanks in advance for any help.

DL