Old Toaster Polarity?

jawalter · Jan 12, 2006

Hello,

A neighbor of my mothers has an old Morphy-Richards TU1D (TUID?) pop-up toaster that she claimed stopped working. The mint green toaster is in excellent (almost like new) condition. The toaster is wired for 120VAC and comes with a standard 2 blade non-polarized plug. The width of the blades on the "old" plug are the same, so the plug can be flipped over interchanging the line voltage and the neutral conductor connections to the toaster. Fortunately, there wasn't anything wrong with the toaster. All I did to make it work was to unplug it, then I flipped the plug over and plugged the toaster back in to the same receptacle. The toaster only seems to work when the line voltage is applied to a specific blade on the plug. Can you explain why?

Thanks

davedottcom · Jan 12, 2006

Re: Old Toaster Polarity?

Loose connection in the cord or male plug?

steve66 · Jan 12, 2006

Re: Old Toaster Polarity?

Since the voltage is AC, and there is no ground connection to give the toaster a reference, it really can't make any difference to the toaster which way the plug is put in.

I agree with Davedotcom. Its a loose connection, or maybe a bad receptacle.

One more possibility: maybe it has a bad thermal breaker or fuse that breaks the circuit when it gets hot, and recloses when it cools down. If that is the case, you might be able to get a replacement at radio shack.

Steve

charlie b · Jan 12, 2006

Re: Old Toaster Polarity?

A key clue is her statement to the effect that it quit working. That tells me that it had worked once, and perhaps even worked recently. My first question is always going to be, "what happened in the mean time?" Did she move it to the other side of the kitchen? Did she plug it into a different receptacle? Did she accidentally drop it? Also, has it been sitting idle for a long time, or does she use it every morning?

My next series of questions would be along the lines of "have you tried . . . ?" When you were troubleshooting, did you try any of these tests:

Reverse the plug, see if the toaster works, reverse the plug again, see if the toaster works, reverse the plug again, see if the toaster works, repeat several more times. The intent is to prove or disprove your theory that the toaster only works when plugged in a certain way.

With the plug inserted in a receptacle, and with the toaster running (i.e., heating), wiggle the cord, to see if the toaster turns off.

Plug the toaster into other receptacles. Plug something else into each receptacle. See if there is a problem with the receptacle.

Unplug the toaster, open it up, and look at the power connection. Look for loose connections or bad solder joints.

Wes G · Jan 12, 2006

Re: Old Toaster Polarity?

Originally posted by charlie b:
My next series of questions would be along the lines of "have you tried . . . ?" When you were troubleshooting, did you try any of these tests:


Reverse the plug, see if the toaster works, reverse the plug again, see if the toaster works, reverse the plug again, see if the toaster works, repeat several more times. The intent is to prove or disprove your theory that the toaster only works when plugged in a certain way.



With the plug inserted in a receptacle, and with the toaster running (i.e., heating), wiggle the cord, to see if the toaster turns off.



Plug the toaster into other receptacles. Plug something else into each receptacle. See if there is a problem with the receptacle.



Unplug the toaster, open it up, and look at the power connection. Look for loose connections or bad solder joints.

I like your list! If I had to guess, My #1 would be your #2. With older electrical equipment, I have found the most frequent cause of this type of failure to be broken wire in the cord right next to the plug due to metal fatigue from being bent many times in the same spot.

Turning the plug around makes the wire hang differently to where the internal wires touch and make connection

___________________
Wes Gerrans
Instructor
Northwest Kansas technical College
Goodland, KS

Old Toaster Polarity?

jawalter

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davedottcom

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steve66

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charlie b

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Wes G

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