1940s brown crinkle Gibson Magnatone lap steel with static

[Max Greenberg]

I have a 1940s brown crinkle Gibson Magnatone lap steel. When you plug it in there is a lot of static. When you touch the cord where it goes into the jack it must be grounding it and the static stops temporarily. When you lay your hand across the strings as you are plucking strings it stops, but when you want to play an open chord, there's the static, as loud as ever. I took it to a guitar tech and he found a copper-looking ground wire loose inside, which he re-attached. Now it produces more static than ever. I also tried plugging it into a battery powered amp since my outlets in my house are not grounded. No difference.

[Jack Hanson]

I would assume you have a "Mastertone" and not a "Magnatone." Your issue likely can be cured by running a ground wire underneath the bridge.