Here is the latest on my LP Jumbo. I just bought an original, used pickup on Ebay. I pulled all the components from the guitar and before swapping pickups, I checked resistance across both the pickup in the guitar and the one off ebay. Both are measuring slightly over 10 ohms across the 2 leads. I left the original pickup in place and cleaned all the components as best I could with contact cleaner, particularly the In/Out switch contacts. After re-assembly I am getting strong sound through my 15W amp, but only in the Out position. I am going through the Mic-in jack on the amp, using a generic XLR 3-pin to 1/4" adaptor. I wonder if I am getting a signal from the In-side of the switch through the adaptor? I have seen a lot of favorable comments on the Shure A95U XLRM adaptor, maybe I should try one? Is there any way to check the pickup, other than resistance? Does anyone know how the In/Out circuit works? Apparently the other controls, Decades, Bass and Treble only function in the IN position.