[PMunks]

Instead of using aluminium foil to short out contacts to force focus confirm & CIF, has anybody tried unscrewing a teleconverter & soldering the contacts inside?

[RioRico]

Upon what TC do you wish to perform surgery? I have a cheap old PK-mount TC with a steel base that automatically shorts the contacts, and M42 TC's that don't -- but I mount those with flanged M42-PK adapters with the paint scraped off the contact area. If your TC has contacts, you DON'T really want to destroy its ability to communicate with the camera.

Yes, metal foil is a pain. For a couple bucks, you can buy a duct-tape size roll of thin metal tape meant for duct repairs. I'm holding a roll that says NASHUA TAPE but has no product number, alas. I have snips of that tape stuck to many of my lenses and mount adapters.