if it's visualy looking good.problems starts on contacts with element.on the tip of contact on elements is silver coting,if looks jelow brownish or starts peeling is gone.Must remain bright silver coating
Inside is two solenoid valve and need to be replaced all q and qex have same problem after a while.Usualy only one is bad but better to replace them both
If you still need bulb I have Fuji 300w 120v works the best for your equipment,and also I have GE 250 120v All is old stock whan stuff was made to last
I think I have dubble tank Comco Sand blaster.Or I can refurbished your what you have and upgrade it to something you haven't see.Let me know if you interested.What type you have?