Results: mixed.
So last week I discovered a serious problem with my '60s Trib: static electricity. Not unlike others (even some Historics) I had seen online, my '60s Trib was generating static along the back of the guitar (esp. in the middle across the chambered cavities, over the plastic cavity covers, and on the wood bridging the jack and control cavities). This crackling noise would clearly come through the amp and ruin my playing experience if I moved at all.
Searched the web, found out that some folks had found relief by shielding, but I honestly didn't want to disturb the original wiring. So I called Gibson CS, which acknowledged that they were aware of the problem and suggested a wipe down with naptha and a polish.
Tried that, of course it did not work.
Since the P90s hum like mothers anyway, I went to the shop. Shielded all cavities with foil. All aluminum grounded (checked with meter).
I measured the hum before and after on a computer, so I could compare wave forms. The result: more hum than before.
User error, I'm sure. I think the issue is with a ground loop that I'll need to track down, what fun.
The good news, though, is that the static is gone! Thank god for half measures to keep my sanity.
So I had to spend a day working on a brand-new $800+ guitar in order to make it usable. That blows.