I just want to point out in answer to the question in my original post, one should not attempt to use a normal 4uF electrolytic (polarized) cap in place of C1. C1 is a bipolar cap, replace it with the Digikey part mentioned in this thread. I read on another site that replacing C1 with a polarized electrolytic will eventually cause it to explode. I can't confirm that this is true or not, but if you're going to the trouble to replace C1, you might as well just use the nonpolarized metal/poly film cap from Digikey. I replaced mine last night, I'll swap the boards this evening and report back.