Where can a new Motherboard be purchased?

@schuylerca55537 the guides are not just there for replacement but can also be used for repair and sometimes you have to remove a board to repair it :-). Anyhow, there are no specific places where you can purchase replacement boards. You will have to scour the internet and see what you come up with. Ebay Craigslist, recyclers etc. are all options. I would consider purchasing an Echo Studio that may be damaged other than the board,. Use that as a donor and harvest the board from that.