Defective Multimeter?

[gorr35]

I'm new to multimeters so this may be a stupid question: I have a new DT830B Multimeter and when I set it to the ohm function it just reads "1". No matter what i'm testing or what range I set it to, it's always at 1....even when not used. Am I doing something wrong or did I buy a bad unit? I do have the red lead in the VmA and black in COM and I tried touching the two leads together to zero it out but still just a "1".

[retiredcaps]

Re: Defective Multimeter?

when I set it to the ohm function it just reads "1". No matter what i'm testing or what range I set it to, it's always at 1....even when not used.

I do have the red lead in the VmA and black in COM and I tried touching the two leads together to zero it out but still just a "1".

"1" means it is out of range or infinite. If it is on any ohm range, it should say "1" because your probes are not touching anything.

Put your multimeter on 200 ohms setting. If you touch the two probes together you should get something like 0.2 ohms. If it reads "1", you probably have a defective multimeter. Check the internal fuse.

Funny, I just got this exact model from someone to try and fix.

[alexanna]

Re: Defective Multimeter?

Dose it work normaly on a voltage setting?A single flash light battery should read 1.5 volts.
How about fuses are they good?

[gorr35]

Re: Defective Multimeter?

Dose it work normaly on a voltage setting?A single flash light battery should read 1.5 volts.
How about fuses are they good?

Yes it works in voltage......i tested a AA battery and it read 1.6. I just got this in the mail yesterday so I don't see how it can be a bad fuse, unless it was just cheaply made.

[alexanna]

Re: Defective Multimeter?

Maybe they forgot to put it in, wouldn’t hurt to check.

[retiredcaps]

Re: Defective Multimeter?

I just got this in the mail yesterday so I don't see how it can be a bad fuse, unless it was just cheaply made.

Back in June 2010, I started down the multimeter path with a generic 830B knockoff. It was 99 cents off ebay. When I received the package, it wouldn't even turn on. More details at

https://www.badcaps.net/forum/showthread.php?t=7557

Here is a picture of the Mastech 830B unit I received yesterday. It won't even turn on. The fuse was blown (I replaced it) and it still won't turn on. So I'm trying to fix it as a learning exercise.

I have sinced learned to stay away from the 830 knockoffs or anything that looks like it. The feedback on amazon.com for this Mastech is not great. Most complaints are that it fails shortly after being used a few times.

[goodpsusearch]

Re: Defective Multimeter?

Here is my multimeter. You say that it is bad??

[gorr35]

Re: Defective Multimeter?

Here is my multimeter. You say that it is bad??

When I asked if it was bad I meant defective.

[goodpsusearch]

Re: Defective Multimeter?

Ok. I ask if it is unreliable.

[Krankshaft]

Re: Defective Multimeter?

First answering your question on any meter I've ever owned OL (out of limits) is displayed when the meter is in resistance mode and the probes aren't measuring anything. Yes if it always says 1 when measuring then yes the meter is defective. Now time for a mini lecture on these meters.

As the old saying goes you get what you pay for. It's a very common occurrence for these extremely cheap MSOs (meter shaped objects) not to work out of the box.

Many people fail to realize that a multimeter is an electrical instrument with current passing through it. If you pay next to noting you will have next to no protection inside the meter from what you're measuring.

Good meters have protection fuses, MOVs to dampen high voltage spikes and prevent the meter from exploding in your hand should you put a probe in the wrong place when measuring line powered equipment. Good meters also have well made probes with thick rugged insulation certified at the meters Cat rating. Instead of whatever cheap wire Hong Kong Flyapart LLC could find. Probe jacks are also made so that the probes plug tightly and don't arc.

About cat ratings:

http://www.coleparmer.com/techinfo/t...eter.htm&ID=16

The hallmark of a cheap meter is that HFE transistor gain measurement port to lure in unsuspecting shoppers to buy their meter since it has an extra feature that others don't.

Unless you're measuring harmless battery operated equipment or unconnected components like resistors I wouldn't use that meter. There are plenty of decent meters out there for $50 bucks at that price you can at least get something safe. You're safety is worth more than 99 cents I take it?

A video on decent 50 dollar meters:

http://www.youtube.com/watch?v=ZoeUgMFLyAw

</END SAFETY RANT>

[Th3_uN1Qu3]

Re: Defective Multimeter?

The hallmark of a cheap meter is that HFE transistor gain measurement port to lure in unsuspecting shoppers to buy their meter since it has an extra feature that others don't.

I've actually found that tester useful on certain occasions.

Anyway, i own two 830Bs, one DT9208A and one UT60E. Here's my thoughts on each:

Uni-T 830B: Cheap, good. Gets confused with voltage spikes though. Had it for a few years now. Replaced the probes somewhere down the line as the originals were crap. Sure, it doesn't measure much, but it's accurate in what it does.
Mastech 830B: Same as the Uni-T, just that it has a nicer case, bigger LCD and a hold button. And *slightly* better quality probes.
DT9208A: Good at first, but went quite off after i dropped it. Turns out they're using lowest quality trimpots - and LOTS of them! I would replace the trimpots with multiturn units and recalibrate it, but i would pay for the trimpots more than the meter itself is worth. The only part that uses decent trimpots is the frequency meter. Came with crap probes. Only good parts of it are the capacitance meter and temperature probe.
Uni-T UT60E- Now we're talking. CAT IV rated probes, fused 10A range, mA range goes up to 400mA, big, backlit display, and hella good battery life. Very good accuracy, frequency/duty cycle meter up to 50MHz (even though it says only up to 10 in the manual) The only sign that the battery is going low is that the backlight has gotten dimmer. It's yet to throw the low battery icon. TrueRMS on AC, doesn't get confused by voltage spikes. PC connection via optically isolated serial cable. My only complaint is the slow autorange. Well worth the cash.

Bottom line: A good meter is nice to have, but you can get away with one of the cheaper ones if you only need basic functions and buy some good probes. The probes that come with cheap meters are a major safety risk and should not be used.

[retiredcaps]

Re: Defective Multimeter?

Here is my multimeter. You say that it is bad??

I don't know what your reference voltage is from the fan to say if it is accurate or not.

[retiredcaps]

Re: Defective Multimeter?

There are plenty of decent meters out there for $50 bucks at that price you can at least get something safe.

There are a lot of good new and used multimeters on ebay USA. Over the last month, I have seen bids for many good quality used Flukes in the $25 range. Brand names like Amprobe/Wavtek/Meterman, Greenlee, and others are in the $10 to $20 range.

All the above multimeters have the features that Krankshaft talk about. Of course, it requires some patience and bidding discipline to get these deals.

Sadly, the number of sellers willing to ship to Canada is tiny.

[goodpsusearch]

Re: Defective Multimeter?

The probes that come with cheap meters are a major safety risk and should not be used.

Why???

[Th3_uN1Qu3]

Re: Defective Multimeter?

#1. The insulation is thin and dodgy.
#2. The finger guards are too small.
#3. They have a habit of breaking while you're probing things and the wire always brushes your hand when you lift the probe without realizing that the wire got cut.
#4. The wire is thin too so they melt when measuring currents higher than 4A.

Enough?

[goodpsusearch]

Re: Defective Multimeter?

I understand now. Thanks!

#3 has happened to me already but I used my solder iron to reconnect the probe to the cable.


One year ago, I accidentally put the probes of my multimeter at 240V AC while it was at Ohm mode. After that, it couldn't test resistance..

I opened it and with a help of a tech friend we found that an smd resistor was open. He replaced that resistor with a common resistor (not smd) and it worked again.

[retiredcaps]

Re: Defective Multimeter?

The probes that I got with my 99 cent ebay cheapie are unreliable as well. When I plug them into a Fluke 75, I get fluctuating ohms readings between 0.3 and 12.5 ohms when touching the two together.

So the ebay 830 was DOA and the probes might have a possible break in the wire.

The mastech 830 probes are marginally better. On the Fluke 75, they read a solid 0.2 ohms.

[Th3_uN1Qu3]

Re: Defective Multimeter?

One year ago, I accidentally put the probes of my multimeter at 240V AC while it was at Ohm mode. After that, it couldn't test resistance.

When i bought my Uni-T UT60E i demanded that it be plugged in to the mains for a voltage reading then switched between all ranges while being plugged in. No problems. The manual tells me it's protected up to 1kV on all ranges. You get what you pay for. I actually used it for a 1.5kV measurement once. Didn't blow up. Certainly not something you'd trust a cheap meter to do.

The mastech 830 probes are marginally better. On the Fluke 75, they read a solid 0.2 ohms.

That's what they read on a 830B as well... maybe 0.3 sometimes. 0.2 ohms isn't enough for current measurements. Though they probably do it as a measure of precaution - so the probes melt before the shunt catches fire. On my UT60E touching the probes together = 0.0. Though it does take a little till it reaches zero.

[mathog]

Re: Defective Multimeter?

As the old saying goes you get what you pay for.

True, but I am fond of the Harbor Freight multimeters which can be purchased for just a couple of bucks (price varies as they are on sale about half the time.) They are accurate enough for what I do. The flip side of getting what you pay for, is not having to worry much about breaking a cheap tool.

I wouldn't mind buying some better probes though, if I could find some that would plug in. (The wires on the probes they come with are pretty thin.)

[jpartanen]

Re: Defective Multimeter?

"Happy" owner of a Mastech M-830B here... The meter is ~6 yrs old, bought from a department store. Didn't get a manual in Finnish, clearly a violation of regulations. Current measurement stopped working 4 yrs ago, fuse's good. Turn limiter broke 3 yrs ago, selector now spins freely. Set it between some positions and you have yourself a timer. 20VDC position misplaces the comma.

EU's product safety database says the following of Mastech M-830B:
Risk of electric shock/fire. Unsafe creepage distances; unsafe internal insulation; incompliant fuse. The multimeter does not comply with the Low Voltage Directive and the relevant European standards.

Also other copies are affected, see http://ec.europa.eu/consumers/dyna/r...rchives_en.cfm and search for multimeter