I have a Collins ART-13 that has 7 pin Micanol medium size sockets for its 1625 tubes. The sockets are quite loose and I was wondering if anyone here would be willing to share any experiences or tips in tightening these sockets. Access to these sockets from the bottom seems very tight and so working from the top side would be best.

I have resorted to using a dentist's explorer (tool that has tip like needle) to get around and bend inward the leaves of the springs after a good dousing of deoxit and a reaming with pipe cleaners.

These get and I suppose the metal just fatigues at some point.

Replacement ceramic types are still available, got a bunch on Ebay a couple of years back when building an amp. Sometody here might have some if you need them, try WTB adin Radio Classified Forum here.

Agree with Codefox; I've been using an angled dentist's pick to retension sockets of all sorts for years. I've never run across anything that works better.

Larry