Re: Testing timing of Red Atom Modules Home › Forum › Ask A Member › Testing timing of Red Atom Modules › Re: Testing timing of Red Atom Modules debeReplies: 103Topics: 0 June 2, 2018 at 10:27 pm #77303 Don’t see why the BC337 is failing as it is what is in the original Atom modules. The BU806 is worth a try, the spec sheet doesn’t give Hfe gain of the transistor, if its not high enough it wont work. Some pictures of the original red module.