Problem solved, one of the output transistors (2n3866) had turned into a diode and after a quick change the coupler section works normally
The transistors are getting quite warm so i added a cooling star on each, it can't hurt. I used the occation to solder ut the mysterius "attenuator", as the drawing shows, consisting og 12 diodes and 3 caps, clamping down the input voltage to about 4V !
Thank you for all help