You can throw a "WTB" on this board in the 1300 classifieds and maybe on the vtxoa.com website. Try e-bay as well. Other than that, dealer would be the only other choice I can think of.
I agree with DAR. Get the service manual. It has the same info as the owners manual plus more! Including photographs, diagrams, etc. I bought the service manual on Ebay for $50, and it is worth every penny.