This one in Carrolton, and also with heating issues.
Near as I can tell the only difference between these older kilns and “modern” ones are the controls. Not coming up to temp has to be a heating element or controller issue. Either of those are easy to diagnose and fix. There appear to be a number of open source controller projects. Then all you need is to watch your electric meter spin really fast.
All of this assumes the lining and cover are in good shape.