Rapidroy: My guess, cold solder joint?
Quite
possible - apart from obviously broken components, bad caps and bad
solders probably cause the most problems with old B&O kit. Bad
solders are more common in TVs because of thermal stress but you often
see them elsewhere too. Wave soldering wasn't that advanced back then,
and occasionally you see a problem that was hand made in Denmark
Hope you can now enjoy the deck for a long time