Hi there. I recently purchased a second hand M1 passive for my Martin 000-16GT. Love the sound of it but am having problems with the strap end pin connection between jack and guitar lead. It's quite loose and the guitar cable jack won't connect properly. It just feels loose and doesn't have a snug fit. I have tried with several different leads - Planet Waves circuit breaker, Switchcraft lead with SC plugs, all with same problem.

Any ideas on how to tighten up this connection?