McCormack TLC-1 loose front panel knobs

replace them with vintage ones that have locking screw and not snap-in. do your research to find matching ones. there are also wood knobs for sale often offered here, but very pricey. they claim to improve performance which i doubt, but definitely imrpove looks of equipment.
The other way is to use nail polish with one thin layer over the knob pins (if the pins are not plastic). Once you snap your knob on, to remove you may use some screwdriver as lever that will be able to crack the polish and release your knob. Also within the time it may go off by itself and that's when you can repeat with another layer.

Are you sure there is not a very small hex head set screw?
They usually put them on the underside where they are not readily visible.
You can also email or call SMc Audio.

Hi Kilowat3 -

The TLC-1 knobs are secured with #4-40 hex-head set screws, and you will need a .050" hex driver to tighten them. The original set screws were steel but I have now replaced them with longer Stainless Steel screws that do a better job of staying tight.

Please contact me directly if you have further questions.

Best regards,

Steve McCormack
SMc Audio