Faulty Stingray 5

Hi. This is my first ever post.
My Stingray 5 has stopped working, and my local luthier is unable to diagnose the fault. The soldered connections to the input jack seem intact. I have put a fresh battery in. On my last gig I managed to get a signal by pushing the jack plug to one side and taping the lead to the bass to maintain the (somewhat tenuous!) connection.
My question is: is the fault more likely to be caused by a faulty input jack, a failed pre-amp, or a loose connection elsewhere?
All suggestions welcome!
Thanks, people…