I think my multimeter is crap.

[Guest]

I can't get a good resistance reading on any pair of coils. Amprobe brand, I think I got it at AAP, so it wouldn't surprise me if it's a piece of crap.

I keep sticking the leads into the plug caps and it's completely erratic, then an hour later it'll read steady, then an hour later, it'll give me another steady reading, but different. New batteries don't help.

Am I doing something wrong?

[mike_of_bbg]

I think I probably have the same one. Try turning it on with the leads touching each other (so they should have 0 resistance). I do that when I get funny disconnected resistance readings. Seems to calm it down quite a bit - particularly at low resistance. Mine will still usually register ah ohm or two on the lowest setting.

[UncleMike]

I think I probably have the same one. Try turning it on with the leads touching each other (so they should have 0 resistance). I do that when I get funny disconnected resistance readings. Seems to calm it down quite a bit - particularly at low resistance. Mine will still usually register ah ohm or two on the lowest setting.

Yikes!

It didn't like that at all. Made it give all kinds of different readings, one after the other.

[Baatfam]

I've had a lot of leads go bad...just a thought.

[UncleMike]

I've had a lot of leads go bad...just a thought.

Honestly, I never even realized or thought that a lead could go bad.

But they do seem to give a fine reading when testing voltage ...

[Texas Don]

Your meter actually uses it's internal battery to send a tiny amount of current through the leads to measure resistance. The amount of current "sent out" on one lead and "received back" on the other provides the basis for an internal chip to calculate the resistance value. When's the last time that you replaced the battery in your meter? Probably a fresh battery will make a world of difference.
Don

[UncleMike]

Your meter actually uses it's internal battery to send a tiny amount of current through the leads to measure resistance. The amount of current "sent out" on one lead and "received back" on the other provides the basis for an internal chip to calculate the resistance value. When's the last time that you replaced the battery in your meter? Probably a fresh battery will make a world of difference.
Don

I just replaced the 9v. If you're telling me there's yet another battery in the little bastard, I've never replaced it, and it's about three or four years old.

[Marine36]

I use a multimeter on a daily basis. I have never had a problem with Amprobe brand meters but I regularly use a Fluke. It is recommended that your meter is calibrated on a yearly basis. However testing coils is not a critcal measurement.

Erratic readings or readings that seem to change constantly are signs of a bad battery, leads, or a bad meter. Take it to your local radio shack and ask the clerk if you can test it by using several resistors of known value they will have in stock. You will be able to find new leads there as well and a new battery. Yes you said you changed the battery so at least double check the connection.

Also if you have any buttons other than the dial to change functions that none of them are stuck down.

My guess is the leads or more importantly the connection at the meter. Are they tight? Are you in the right holes? Most meters have a different lead connection spot for resistance/voltage and amperage.

[argonsagas]

I can't get a good resistance reading on any pair of coils. Amprobe brand, I think I got it at AAP, so it wouldn't surprise me if it's a piece of crap.

I keep sticking the leads into the plug caps and it's completely erratic, then an hour later it'll read steady, then an hour later, it'll give me another steady reading, but different. New batteries don't help.

Am I doing something wrong?

Sounds like you are describing a sexual episode. Should this be in the Off topic section?


Let's add the old adage here: you get what you pay for.

[Redman]

Meter on resistance settings. Hold two probe tips togeter firmly. SHould read 0 ohms. Wiggle lead wires around, wiggle lead plugs (at meter) around - should stay at 0 ohms all the time the probe tips are together. If it does not then is prblem with meter leads or plugs.

My first suspision when measuring resistance if I suspect anything is that the probe tips are not making good contact with the part being checked. Make sure to scratch the pointy tip of the probe tip into the surface of the part to get past any surface corrosion and into the bare metal.

Ah. A resistance meter works by applying a voltage (a reason why it needs a battery) and then is acaully measurinig the current, and then based on the voltage and current then determines the resistance. To make a mechanical analogy is sort of like applying a pressure and then measuring the flow and then based on pressure and flow can then calculate the restriction (small opening or big opening) in the pipe.

[Calvin Blackmore]

Do you have the caps that can be disassembled?
the ones that have a ressitor core inside?

I tested mine once upon a time and got erratic readings whcih were only fixed by dissasembly and cleaning of internal corrosion.

dunno why....

but this is happening when bypassing the caps as well eh?

[UncleMike]

Do you have the caps that can be disassembled?
the ones that have a ressitor core inside?

I tested mine once upon a time and got erratic readings whcih were only fixed by dissasembly and cleaning of internal corrosion.

dunno why....

but this is happening when bypassing the caps as well eh?

Yeah. Maybe I'm just plugging the leads in incorrectly?

[Calvin Blackmore]

Yeah. Maybe I'm just plugging the leads in incorrectly?

my leads had to be clipped back a bit as the threaded pin they go onto had sort of um twisted them all to hell making for a possible intemittent contact if twisted.

maybe also push a spark plug in and measure that way as it a heck of a lot easier that probing a spark plug cap....
of course resistor plugs might skew your readings.....

[Rkt-Rch]

Short (put both leads together) in ohm's mode or continuity mode and you SHOULD see zero ohms or here a beep of some sort if useing that mode. While they are shorted together wiggle them around and see if it changes/jumps. Some meters also have a fuse inside. Some have two batterys.

If all else fails just go pick up one they are fairly cheap. Tobad I have about 6 or 7 sitting around my garage.

[BlackStar]

Do you have the caps that can be disassembled?
the ones that have a ressitor core inside?

I tested mine once upon a time and got erratic readings whcih were only fixed by dissasembly and cleaning of internal corrosion.

dunno why....

but this is happening when bypassing the caps as well eh?

I had the exact same issue (I also thought I had a meter / lead problem) I replaced the resistive pelets with ink pen springs and got good steady readings. I started running resistor plugs instead.