[wdfifteen]

I was a tech at one of those. People brought the most roached-out crap in and wanted us to spend time trying to fix it. There wasn't much that was salvageable. Steve's suggestions for tools is right on.

A quick anecdote, if you don't mind.
I was the fix-it guy at the hardware store where I worked when I was in college. Two people brought in identical clothing irons to be repaired. One of them only needed a cord, the other one was toast (parts cost more than a new iron). I fixed the one with the cord. I was in the back room (the shop) when the lady came in to pick it up. The guy working the register yelled at me that she was there to pick her iron up. I threw the junk iron out into the isle, and it crashed to the floor and bounced around. He, being a cool guy, picked it up and told the customer it would be $5.95 for the repair. She timidly asked if he was sure it was OK after being tossed on the floor. He said, "Oh sure, these things are indestructible." We were both trying to hold down our laughter as the lady pulled out her purse to pay. After I came out and told her I'd sent out the wrong iron, I felt so bad, I plugged it in and demonstrated that it worked fine.
We were always playing cruel jokes on customers when the boss wasn't around.