Obviously double double check your soldering- easy to get a 'dry' joint somewhere- check the EF86 is OK & one issue I had with the DC30 was the insert jacks for efx send/returns weren't making a good contact- I solved this by cleaning the jack make/break contacts with mild abrasive & switch cleaner and re-tensioning the contacts slightly-  you can check continuity easily across the send/returns with a multimeter...