Control switch
Seeing that control switch on that dryer brings back memories. That thing can be a problem. I had a TOL DE810, maybe? Its been too many years to remember for sure but I bought it in 1984. It was totally electronic. I don't even think it had any selections for timed drying. Anyways, after a few years it would run okay, but quit heating somewhere along the line after you started a load. If you would re-start the load, it would heat fine for awhile, then quit again. So that lead me to the control switch. If I held the push to start button down, it would heat fine. When you push to start it moves a bakelite strip sideways inside of this control, causing some contact points to close and others to open. Over time, this bakelite wears down somehow, and just the small vibration of the dryer running causes this strip to move, allowing the points for the heating element to become open, and you loose heat. The only way to fix this that I know of, was to replace the control switch with a new one. They would last several years, but eventually, I had to replace it again. Other than that, I had no problems, but that switch can cause you some problems. Just an FYI that might help someone with the same problem, figure out how to fix it quicker.