Why would a test point be showing V instead of mV?

[aphex]

Something seems to be amiss here. My auto ranging multimeter is reporting back 20V on a test spot that should be 20mV.

?

 

[SirChadwick]

Man, you just made me feel dumb. I'm lost.

 

[aphex]

 

[MotF Bane]

Are you sure your multimeter is in working order? Check it on something else that you absolutely know the value of?

 

[bobdole369]

Either your meter is wrong, or there really is 1000 times more voltage than should exist. Pick one. Use a different meter to test your hypothesis.

 

[aphex]

the meter seems to be working fine

 

[aphex]

the meter seems to be working fine

 

[DisgruntledVirus]

Wrong selection in measurements?

 

[NL5]

Operator error.

 

[NaOH]

You gotta describe to us what, and how you're measuring.

 

[bobdole369]

Then there exists 1000 times the expected voltage at a test point. Schematic?

 

[vshah]

does your multimeter auto-set range?

 

[aphex]

Originally posted by: vshah
does your multimeter auto-set range?

Yes, and if I take it out of auto range and set it to mV it says OL

 

[aphex]

Originally posted by: bobdole369
Then there exists 1000 times the expected voltage at a test point. Schematic?

http://www.diyforums.org/MiniMAX/MiniMAXschematic.php

I'm testing at TB1L/TB1R and TB2L/TB2R

 

[PlasmaBomb]

What is the make and model of the multimeter?

 

[aphex]

Originally posted by: PlasmaBomb
What is the make and model of the multimeter?

Sears Craftsman 82314

Owners Manual - http://download.sears.com/own/03482314e.pdf

 

[MrPickins]

I'd run to walmart and buy a $5 DMM to get a second opinion on the voltage.

 

[aphex]

Originally posted by: MrPickins
I'd run to walmart and buy a $5 DMM to get a second opinion on the voltage.

I have a $5 one from Harbor Freight. Set to DCV 200 its showing 20

Is that mV or V? (This meter doesn't show)

EDIT: From what I can tell, thats showing V as well. It would need to be in 2000m or 200m to show mV, which both show OL

 

[sdifox]

Originally posted by: aphex

Originally posted by: MrPickins
I'd run to walmart and buy a $5 DMM to get a second opinion on the voltage.

I have a $5 one from Harbor Freight. Set to DCV 200 its showing 20

Is that mV or V? (This meter doesn't show)

20V

DCV200 means max is 200V

You got a short somewhere is what I can think of.

 

[MrPickins]

Originally posted by: sdifox

Originally posted by: aphex

Originally posted by: MrPickins
I'd run to walmart and buy a $5 DMM to get a second opinion on the voltage.

I have a $5 one from Harbor Freight. Set to DCV 200 its showing 20

Is that mV or V? (This meter doesn't show)

20V

DCV200 means max is 200V

You got a short somewhere is what I can think of.

This.

 

[Cuular]

Some resistor is malfunctioning and not adding the resistance to the circuit that it should?

 

[RU482]

my meter does funny stuff like that when the battery is low

 

[cirthix]

check for a missing ground connection somewhere. I'm guessing that 20v is your supply voltage. if you have a broken ground connection, it could very well be pulled to the supply voltage.

 

[So]

Originally posted by: cirthix
check for a missing ground connection somewhere. I'm guessing that 20v is your supply voltage. if you have a broken ground connection, it could very well be pulled to the supply voltage.

Yeah. I'd trust two meters over what my instinct says it "should" be.