After removing the battery, lens and opening the back cover/pressure plate, I just run a very small amount of acetone into the groove between the silk-screened speed indicator disk and the knob - off the tip of a scalpel blade. The glue normally then melts allowing the indicator disk to be levered up with a sharpened wooden splinter. Sharpened splinters are very easy to create with a knife and a toothpick.
Instead of a wooden splinter you could use a suction cup.
The emphasis here is on "VERY SMALL AMOUNT" (of solvent) as too much will ruin the viewfinder's plastic fresnel screen...
A gentler alternative is to try iso-propyl alcohol first, as sometimes it will do the job. With some plastics even the fumes from acetone will damage the fresnel screen...
As always, try this method on a junk camera first.
Melting the glue and using a wooden splinter avoids that pin-shaped dent you sometimes see on the speed knob/indicator disk on repaired cameras where people have levered it up with a metal tool.
As soon as it has softened the glue, turn the camera upside down to make sure any excess solvent runs down and out of the camera.
The Super TL is a surprisingly useful camera in my opinion and grossly underrated by most people, but then I also have five PracticaMat's. Love that stop-down lever/meter switch!
