I have a 4 burner, electric ignition Bosch, Model# NHT712AUC. The parts are discontinued. I can't buy a glass type white top anymore as that isn't in style any more. The igniters do not go on(sometimes it work intermittently). Is there a source for the parts mounted on the underside that would be replacement type parts. I've replace the ceramic/electrode type igniters but that isn't it. A repairman told me there are parts mounted on it's underside that need to be changed. Any info would be appreciated. I think it is part # 820066 (module) any substitutions(00421256) or sources?