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General Category => General Discussion => Topic started by: crebble on Nov 14, 2012, 02:15 pm

Title: Multimeter shows 3x actual voltage
Post by: crebble on Nov 14, 2012, 02:15 pm
hey people,

since I measured a cap my multimeter has been showing the wrong values for volt. a full 1,5V AA battery shows around 6,5V and a 9V battery shows around 25~30V.

I took the meter apart but can't see any immediate damages or shorts.

Does anyone know what is actually wrong with it?
Title: Re: Multimeter shows 3x actual voltage
Post by: robtillaart on Nov 15, 2012, 07:22 pm

does it show this factor on every selection? or 0-10V only?
Do you have a schematic of your voltmeter?
Title: Re: Multimeter shows 3x actual voltage
Post by: retrolefty on Nov 15, 2012, 07:39 pm
Probably 'cooked' one of the input voltage divider ranging resistors, but other failure modes are possible. Time to get a new meter. The best digital multimeter have pretty good input protection circuitry up to the maximum rated input voltage. Do you have link to your specific meter?

Lefty
Title: Re: Multimeter shows 3x actual voltage
Post by: stoopkid on Nov 20, 2012, 06:10 am
I friend a cheap multimeter and it unfortunately just gave me incorrect readings rather than any kind of indication that it was broken.
Title: Re: Multimeter shows 3x actual voltage
Post by: retrolefty on Nov 20, 2012, 06:13 am

I friend a cheap multimeter and it unfortunately just gave me incorrect readings rather than any kind of indication that it was broken.


?
Title: Re: Multimeter shows 3x actual voltage
Post by: stoopkid on Nov 20, 2012, 06:15 am
Y'heard me!
Title: Re: Multimeter shows 3x actual voltage
Post by: crebble on Nov 24, 2012, 07:19 pm

Y'heard me!


I like your style.

Anyway, the multimeter is a HoldPeak HP-760B

Also, I have an older one that has the same problem (also tried measuring a cap with it..), it doesn't have a model or brand name though.
I've taken them both apart, to see if any resistors are burnt or any other damages are visible. No luck so far.

Shame really, I liked the HoldPeak Multimeter.