Step 1: You tell Me Your problem.
Step 2: I spend some time with You asking questions because You are My eyes, hands, and ears (in Your case i have seen this alot so I was able to make a decision quickly)
Step 3: I spend a few minutes giving You some basic information, where to get the parts, how much they will cost etc.
Step 4: You decide if it is economical for You to repair it or replace it, in Your case a $200 repair on a $179 dollar microwave (this which I knew) This is where most people will say " I would probably just be better off buying a new one " I gave nothing more than facts this decision is made on thier own.
Step 5: Either We are done or you want to get the parts if You where going to fix it all you had to do is tell Me and Thats when I would spend the 45+ minutes giving detailed instructions on replacing the parts, Why would I do this up front when there is a good chance You wont even fix it?
If Your not going to fix it and go buy a new one Why would it be even necessary to type all that out.... I am not given any thing here except a way to comunicate with You I use My own materials, resources, and experience to guide My customers in doing repairs on thier own.
If You feel You have been had ask for a refund.
If My diagram was insufficient to do the repair, YOU should of asked for more details I have no clue how much or little you know and I can answer a lot more questions if I am not wasting time typing out instructions for someone I have no clue will even use them.
As far as if the part will fix it I am coming up on My 20,000 in home service call at My primary job and I can honestly say that close to 50 have been Your same problem.
You have a nice day!