Serger woes

My serger started acting all bizarre while Sarah was here last August. I disassembled it and figured out what was the cause, fixed it, and off I went making more and more baby items. I am sure I serged miles of lengths of diapers, wipes, and washcloths.
I use my serger at least twice a week and it is by far the most versatile tool I own. It started making a horrible hammering noise last night after I made an Infinity Dress. I noticed that my throat plate was cracked and switched out for my narrow hem plate, switched up to 2-thread serging, and moved onto hemming off a lightweight material. One side into it, the hammering got crazy noisy and that was it. Off went the power, trimmed up the best I could with the project, and now I am trying to figure out what the heck is going on. The feed dogs almost look like they are timed off-or-are jumping up to high-or-hitting/missing/catching the plate. Considering (1) how much it costs to repair, (2) how mechanical Mike & I are, (3) and how totally cheap I am, we shall fix it! I did it once and it shall be done again!
Wish us luck!