Kitchen Gas Appliances - GE gas dryer - how it works?

Hello,
I have GS gas dryer model (one of those, from manual) DBL333, DCL333, DVL223, NLL113, NVL333. It is eight years old. With three kids it has a load every day.
My family is back from vacation and - how convenient :) - it stopped working :)
Two days ago I was cleaning the area around it and I notices that the "exhaust" pipe was not connected. I put it back and right after that I noticed that it took twice time to dry that load. Today I don't get any heat with the pipe on or off... The rest if fine: it turns on and off, blows the air as before...
First of, could you please tell me how this thing works inside: how gas is getting converted into the heat? Maybe I can read a operation principles (so to speak) somewhere, maybe there is a diagram of what's inside.
Secondly, it is serviceable? What is wrong with it and how to fix this thing?
Thanks a lot in advance,
Alex.

First give us model # so we can see what machine you have. When you hooked up vent tube it was probably blocked and overheated dryer. Usually a thermo fuse or thermostat opens and dryer will not heat. After you get dryer working vent needs to be cleaned. Air from back of dryer should be same as air coming out of house.

Thanks,
My wife was on my neck - I called a pro. It was on of the solenoids.