baaaaaa! Wrong answer. 6C33C take special tester. Doubt you'll find any radio, TV, guitar shop with one. There is a person on this forum who sells them, tested, for $60 a piece IIRC (just do a search in classified section). Perhaps he might be able to test for you. Also, I used to purchase them at PartsConnexion.com, which also tested them. They might help as well.