The gas dryer is electrically energized and hums, although the drum doesn’t turn, when the door is closed or open. The only method of turning it off is to either set the timer to zero or unplug it. The drum doesn’t turn when the door is closed and the timer has minutes on it. Pushing the start button makes no difference.
Look in and see if the belt is broken. From what you are describing it sounds like the gas assembly is trying to fire but the drum ain’t turning. To replace the belt you are gonna have to remove the front panel. You may as well give it a good cleaning while you are at it. Also inspect the slides and rear bearing.
OK, back from work and able to flip front panel and see that the belt is in place. I guess I’ll look to the motor. It is nearly 18 years old so that wouldn’t be too surprising. Hmmm, if it’s the motor, do I replace it or buy a new dryer? I’ve replaced the slides and rear bearing, some gas valve parts and been through a couple of igniters over the years.
These newer appliances are not worthy to stand next to a fine old machine like that. The motor is really the heart of the dryer. I would definately replace it.