Alright guys, so I've been working on making some of my own chips lately. Got a USB K150 programmer and a homemade ghetto serial programmer which I got the schematic for from this site. I've programmed chips using the MM3 12F629 Hex and it works perfectly on said 12F629. I've also programmed the MM3 Hex file meant for a 12C508 onto a 12F508 rewritable chip and it works fine. Problem is I am unable to get any actual 12C508 to work on a PS1 that I program. I've already wasted a few chips and I'm not in a hurry to waste more. I've tried MM3 and Mayumi v4 Hex files on 12C508A's with different settings and every time it fails to work on either PS1s I try it on , meanwhile all my other non-12C508A chips seem to work. I even have 2 pre-programmed 12C508As which were purchased from a member of this site which both work on the systems. Note that the ghetto programmer listed above will not read any 12C508As I throw at it; I tried ICprog and Winpic. It will read/program 12F629 and 12F508 fine, but not 12C508A. Not a huge problem because I have my USB K150 which can read and program them. Except they don't work when I test them. I've made sure I set the OSCCAL value like I'm supposed to. What gives?? I've tried programming the Mayumi v4 Hex onto a 12F508 and it flat out refuses to even program properly, doesn't matter which programmer or software I use. But I can confirm that the MM3 Hex designed for 12C508 works fine on 12F508, or at least on the systems I've tested it with. Any ideas on how to get these 12C508A's to work properly? Can someone refresh me of what settings I should use. Like I said, I've tried different settings but maybe I'm missing something. Thanks in advance for any help.