Stating the obvious, but have you changed the battery lately?I've not only given them the "back and forth", I have also used de-oxy electronics cleaner, which is usually a temporary fix only. I think I really need a good local guitar tech, but these TBIBT preamps are complicated and fairly rare, so I am quite concerned with finding someone who can do a good job. Letting Pedulla upgrade it would be very expensive and would change the sound of my bass while also taking a very long time. I.e., lots of concerns with this approach. I definitely miss the old days where I could talk to Mike directly.
Fishheadjoe