Amprobe model RS-3 problem

I'll bet that you clamped the current jaws around a 2 or 3 conductor cord, right? If so, your meter will read zero all day, no mater how much current you have in the wires. Oh, and it must be AC current; it won't work on DC. The reason that the meter won't work if clamped around both conductors in the cord is that the fields created by the current cancel each other. You'll have to split the cord so that the clamp only has one of the conductors inside. Then, it should work as advertised (assuming that nothing is defective in the meter). I recommend the line splitter at

It will allow you to check current on an appliance without having to split the cord open to isolate the conductors.

You can download a copy of the manual for your meter from

Cheers!!! Great find!!!

--
Dave M
masondg44 at comcast dot net

One good thing about Alzheimer\'s; you get to meet new people every day.

If that doesn't do it, open up the meter and look for two small diodes connected to the pickup coil on the clamp and check them with a multimeter, they often fail when someone puts too much current through it.

Shaun

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I went back and read my post because I thought that I was very explicit when I said that I "clamped it around a current carrying conductor", meaning one side of the line. I suppose that I should have said that. The diodes sound like a great idea to look into however to open this thing it looks like there are two hex nuts surrounded by a thick sort of plastic shoulder which makes it impossible to get a socket on to. Any ideas? Thanks, Lenny.

Your description is correct, as far as the older models that I've seen. Newer models that also read DC current use a hall effect device for sensing the DC current, from what I've read about them.

If the jaws are laminated steel, they're probably just about indestructable, but if they're formed ferrite material, there may be a break in a "jaw" section, interrupting the induction path. The break might not be a physical fracture from abuse, instead, it could be some foreign material interrupting the magnetic circuit. The parts of a ferrite inductive pickup should meet squarely, with no gaps.

The hex nut locations you described in your follow-up post sound like the associated screw heads may be in recesses on the opposite side, and that the screw heads may have been concealed by some sort of filler that conceals/obscures their location, and also lets the manufacturer know that the case has been opened (voiding any warranty obligations).

In old equipment I've seen asphalt-type filler used to conceal fasteners, and newer equipment a silicone or a hot glue-type filler has been used.

-- Cheers, WB .............

I went back and read my post because I thought that I was very explicit when I said that I "clamped it around a current carrying conductor", meaning one side of the line. I suppose that I should have said that. The diodes sound like a great idea to look into however to open this thing it looks like there are two hex nuts surrounded by a thick sort of plastic shoulder which makes it impossible to get a socket on to. Any ideas? Thanks, Lenny.

I used to use a small pair of needle nose plyers to open them, it's been a while, over 10 years. see if that works.

Shaun

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I got it open.Now I'll have to take it apart and see Thanks Lenny.