I think you mean the hold down plate, which is changed by removing four 12mm M4 screws and pushing the plastic section out, and not the back plate.
If so, and assuming AM3 mounting holes are the same as AM2+, then I believe the only suitable plate is the universal one pictured below.
I don't know where to buy one either, but I'm 90% sure I've got one sitting unused on my desk at home. Happy to post it to you if that's what you're looking for.
edit: found it, slightly different from the photo. I think the one shown above accepts 775 as well, but mine doesn't. The rest of the holes match, and it definitely fitted my am2+ board.
Send me a message through trust with your address and I should be able to get it in the post to you tomorrow. It took me quite a while to source a mounting bracket for my 1366 system so I sympathise.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.