From distant memory, I thought the terminals on the clock were different sizes so impossible to get wrong polarity, unless wires have been spliced in along route of course.
Until you said you had jump started, my initial thought was whether someone had connected battery wrong way round. Still worth checking perhaps?

Last edited by Deejay; 27/01/25 09:45 AM. Reason: typo

Doug
2011 Plus 4 in Rich Maroon

1972 750 “ComDom” sprinter
1958 Triton 650
1992 Triumph Trophy 900