user manual
http://www.cryptomuseum.com/covert/m...p55_manual.pdf
it says , for wire breaks, just knot the ends together, I may try stretched
PTFE spaghetti tube for butt joints of the wire breaks, if interesting
contents.

technical details and pics of a museum grade one
http://vintage-technics.ru/Eng-Minifon_P55.htm

schematic
http://vintage-technics.ru/Minifon%2...nned-P55-1.JPG