Doing something wrong... How do you use a multimeter?

GoldenAge

Well-known member

Donor 2011
Joined
Dec 1, 2010
Messages
1,070
Reaction score
41
Location
Vancouver, Washington
Doing something wrong... How do you use a multimeter?

Hi,

I'm working on my Defender, today, trying to get the wiring cleaned up and proper, detail stuff mostly (coin door lights, etc), and in tracking down the power to the coin lights, I was getting 9v dc on my meter(in DC mode, in AC, I got a solid 0v).

I'm racking my brains trying to understand how a 5v output on a switching supply can possibly give me 9v... Clearly I'm not using my meter right.

So with great embarassment, I ask for help, 'cos this is really driving me nuts! I've used 2 seperate meters on 2 seperate supplies in this game, and when I put the black probe on -5vdc and the red probe on +5vdc, I get 9v... What the *#%#???? It's not the dial, either, I can only get a variance of maybe 1.5v in either direction by tweaking with that.

Is there some funky thing with Defender, or am I just getting so old that I can't remember how to use a meter?

Thanks very much,
Ryan
 
You should never connect from the -5vdc to the +5vdc. All DC voltages should be looked at in relation to ground. Always connect the return lead (usually labeled as ground and normally black) to the same ground reference as the source you are checking.
 
multimeters are your friend!

and exactly what Oryk Zinyo said, 95% of the time the black probe will always be connected to a ground.

I'm still kinda a novice at all this but i have a good amount of volt/multimeter hours under my belt. most meters will come with a manual, if yours didn't you can google the model or just look up basic multimeter use vids on youtube.


Some Vids i found: (i didn't fully watch these just breezed through a lil to see if it would apply) if anyone has a better vid link it up.





Continuity function has always been one of my faves.

also rather than poking into wires like some places tell you to, go to any place that sells fabric/sewing supplies and get a box of T-Pins (wally world has them too) you'll thank me later. they'll save you from breaking probes too.

what brand meter are you using? i really like my fluke 111 (i have a Bluepoint meter also and it's died 2x in less than 1 hour of total use).
 
just be careful not to use the wrong setting and blowing the fuse in your meter (or blowing up your meter if it's un fused). most things that have to do with the isolation transformer and the monitor require the meter to be in AC while most board related will be DC (correct me if i'm wrong).
 
Back
Top Bottom