just took my warm up regulator apart 79 280se. There is nothing to fail on these. take it apart clean everything. put 12vdc across the heater element give it time to heat up, if it does it is good. there are four little screws holding the cover to the steel pressure reducing valve. be careful of the thin stainless steel diaphragm. clean everything. There is an o ring that is probably flattened out..i just cleaned it and reused it. Make sure you evenly torque the little screws back into the regulator. On the larger connection to the steel pressure regulator there is a strainer. tear it out be careful to remove all debris. make a replacement strainer. i did this by using the brass screen on a lawn sprinkler i had. i used several coarses of this along with a piece of the polypropylene strainer mesh used on the paint filters used to strain the paint before you dump it into the spray gun cup. There was nothing wrong with my regulator other than the strainer was plugged..what a gimmick. Bob Fitts