The moral of this story is "caveat emptor". You've got over $250 tied up in a machine that needs repair. If you send it in for repair now, you'll have another $50 in shipping plus repair costs. That's the cost of a new TreasureMaster.

I would cut my losses. Buy a NEW TreasureMaster from a dealer or directly from Whites so that you can use the coil you just purchased, and have a warranty. Look at the Christmas bundle. The accessories will help you recoup the cost of the used machine.

What to do with the used machine? Give it to a kid who wants to learn. They aren't interested in diggin' 8" holes, and may well lose interest in a week. Good karma. Consider it the "cost of education". Or keep it for a backup / tot lot unit. Most tot lot hits are shallow.

Good luck ...