I just purchased a demagnatizer at the local flea market. It is a model I have seen before(we had one where I used to work). Not sure what that is though.

It is a blue box about 3" x 6" footprint with a metal top whick is the demagnatizing surface.


It seems to work except after a bout 30 seconds or so it seems to shut off (stop humming and the red light goes out). At this point you do not want to touch the top because while it is not humming anymore it will discharge into your hand. I learned that the hard way.

If left for awhile longer it turns back on and the cuts out again. If unplugged and shut off and then restarted similar results.


On the side it says not to leave on or transformer will over heat.


I opened it up and everything looks to be in good shape. Nothing burnt and no loose wires or anything.


Is this normal? If not what can the issue be? I dont remember the one we had at work doing this.

It is almost as if it is over heating, cutting out and then it cools down and restarts

The circuit may have a current sense/limiter built in. You know, sort of like a flasher for the turn signals. When the sensor has passed enough current, it automatically shuts down.

This is a way of building and collapsing the magnetic field which can be critical to the demag process - if you leave the device running full on, you can actually start to remag the part.

Or there may be a short which you really will want to fix....

When I setup my new garage shop, I bought one fom Harbor Freight!
It too worked for a few weeks, then it went cold!
After removing the top plate, I noticed all the "Crimp Lugs" were loose!
So I broke out my soldering iron and made sure all the crimp connections were soldered strong!
Now it works every time!

Widgit

It seems to work except after a bout 30 seconds or so it seems to shut off (stop humming and the red light goes out). At this point you do not want to touch the top because while it is not humming anymore it will discharge into your hand. I learned that the hard way.

Is this normal? If not what can the issue be?
It is almost as if it is over heating, cutting out and then it cools down and restarts

If it is cutting out prematurely, I would check the operating current, also being a simple low frequency electro-magnetic device, there should be no 'discharge in to your hand', it almost sounds like you have a leakage to ground and the D.M. is not grounded properly.
Al.

Thanks for the replies all.

Everything inside seems to be wired and connected well. It works fine for about 45 second to a minute then cuts out and comes back on after a @3o second pause.

I will have to dig deeper.

As I said it works fine when it does work and I just cant touch it when it cuts out. If I cant get it to stop what it is doing it will still work for my purposes.

Thanks for the replies all.

Everything inside seems to be wired and connected well. It works fine for about 45 second to a minute then cuts out and comes back on after a @3o second pause.

Mine was doing the same thing!

First look at mine, the connections were tight, but as I looked closer, I could see the crimps were on the insulation and not the conductor! The vibrations were loostening the connections, making them intermitant!

Try soldering EVERYTHING, it can't hurt!

Widgit