Karl
Most likely the problem with your dryer is a bad control board. It is not repairable and has to be replaced. The part number for the new control board is
AP3882440 and you can buy it for $145.49.
The breakdown diagrams for the Maytag dryer with the model number MDG5500AWW you can find here:
Model MDG5500AWW
If you need the complete step by step instructions how to replace the control board I'll be glad to help you.
Good luck.
Gene.