Yes, I know they are only CSR's and reading from a script. I have my EE and prior to that I was an electrician. And I have been in the computer industry for 28 years. Not knowing what a voltmeter was isn't my main concern. It is the lack of common sense. If I say I have verified that proper voltage is coming out of the end of the power cord that is plugged into the back of the computer, there is no reason to suggest that I try another receptacle. It just goes to prove that Apple Support isn't anything special.
Wellll ... if she did not know what a voltmeter was ... she may not know what you meant when you told her you verified the voltage.
What the phone is answered you get a Level 1 Help Desk person. They operate off of a scripted flow chart type of system.
I can assure you this, if you call ....
Verizon
Comcast
Westinghouse
Dell
IBM
Hewlett Packard
Sony
I think you get the idea, you will get the same thing from the first person you talk to.
I remember calling the @Home people for a broadband cable issue. They first person that I spoke too I said this " excuse me but I do not mean to offend you, I have troubleshot this problem and wish to be elevated to at least a level 2 technician. " She told me that elevating a trouble was done by the terminal she was sitting at and she needed to input answers to a few questions. So I let her ask her questions, and I answered them. At the conclusion she said " we need to elevate this to a level 2 ".
I have since had internet service with Verizon (DSL) and two other cable companies and the tech support at level 1 is all the same.
I had a problem with my current cable provider. I flat out told the Level 1 Help Desk person " I know more about this than you will ever learn sitting where you are, I want to speak with a supervisor. "
By the time I was done that cable company was offering me a job!
By the way they are trained to work ONLY from the script. Ask a question, get an answer, move down the chart according to the answer.
On the rare time or two I had to call Apple Support I got nothing but what I had expected. Each problem was dealt with in the manner I anticipated. My years working in the field as a Microsoft and Novell system engineer taught me the ropes.
One of my first jobs long ago was Level 1 Help Desk ... I hated the fact that we were not allowed to deviate from that dang book. But alas it was short time before I escaped that insanity. Now I am retired, sit at home and laugh at the though of using things like Windows,Novell and all that other garbage that is out there.
By the way, I would have tried another known good outlet before I called them, even after checking with a voltmeter because I know that question will come up about trying another outlet. It always does.
A bad outlet could pass voltage through the cord and look good with a voltmeter, but under load it might break contact and cut power. I have seen that condition with a device that draws a lot more current that an iMac though.
I asked her if she knew what a voltmeter was. Her answer was that she did not. And these people are highly qualified techs??? 
