This is why you don't buy cheap multimeters.

[Agent24]

Re: This is why you don't buy cheap multimeters.

Maybe the spring-contacts went out of alignment from the drop? They just sit there on a little plastic ledge (Though you probably already know and have checked that!)

[Th3_uN1Qu3]

Re: This is why you don't buy cheap multimeters.

Well, since then, i have dropped it (a few months ago) and it now displays entirely rubbish. So it's definitely not the range switch which is the problem on mine.

[Agent24]

Re: This is why you don't buy cheap multimeters.

Well, since a couple weeks ago it started working erratically on resistance. More specifically, on the low ranges it reads in the hundreds of ohms even if there's a short, then it slowly counts down to the real value...

I noticed a similar problem (though not as bad) with my meter (it's one of the better-built 830B types)

Turned out to be dirty contacts on the rotary switch.

I cleaned the copper springs on the knob and the gold contacts on the PCB and haven't had the problem since.

[999999999]

Re: This is why you don't buy cheap multimeters.

Sometimes the problem is poor knob contacts, you might try popping it off and cleaning the areas.

[tom66]

Re: This is why you don't buy cheap multimeters.

What were you trying to measure? The explosion does look pretty spectacular.

I can't remember, might have been some high current or voltage. I was just shocked when smoke started pouring out the back of it. It might have been a manufacturing defect because I've still got one of those meters and it's survived many more abuses.

Did it look like this? I got this one free, but not working.

Nope, it was this one: http://www.rapidonline.com/Tools-Equ...st-leads-31052

[severach]

Re: This is why you don't buy cheap multimeters.

The same way everyone ruins their first meter:

"So this plug can supply 15 amps, eh? I can check that with this amp scale."

Then you learn that measuring amps is not like measuring volts.

[retiredcaps]

Re: This is why you don't buy cheap multimeters.

What were you trying to measure? The explosion does look pretty spectacular.

Details at

http://www.eevblog.com/forum/index.php?topic=2585.0

A few times I tried to measure DC on the AC mains - again, no explosions. Perhaps I've been lucky?

See the very popular $4 or less Harbour Freight multimeter on Fluke's test and safety promotional video.

http://assets.fluke.com/video-MULTI/...afety_lab.html

The above multimeter is shown near the end of the video. Unfortunately, there is no timestamp that I can see on where it starts, but you get to see the flames in slow motion.

I think the Harbour Freight multimeter is set to 200 ohms when it is fed with 300+ DC volts.

[momaka]

Re: This is why you don't buy cheap multimeters.

My DT830B blew up, rather spectacular. Hole in the plastic case, charred PCB, not quite sure what went up!

What were you trying to measure? The explosion does look pretty spectacular.

Reason I ask is because I have a 830D (a variant of the 830B). I regularly use it to measure high voltages on the primary of PSUs and whatnot and never had anything bad happen. A few times I tried to measure DC on the AC mains - again, no explosions. Perhaps I've been lucky?
In terms of quality, mine IS pretty much a HongKongFlyAppart LLC production.

[retiredcaps]

Re: This is why you don't buy cheap multimeters.

I was fairly impressed with one of my Mastech cheapies I owned for about two years.

Did it look like this? I got this one free, but not working.

The fuse was blown, but changing the fuse did nothing. I found Q1 shorted in circuit and desoldered it only to find the IC good.

I wouldn't mind fixing it just for educational purposes and using it to measure nimh batteries.

Even though this was made in year 2000 with through hole components, I think it is much higher quality than the cheap 830B that I originally got off ebay. The soldering quality seems better and it is one solid pcb (not the patch job on the input jacks).

[ratdude747]

Re: This is why you don't buy cheap multimeters.

...while the 838 was the HongKongFlyApart, LLC version.

[Krankshaft]

Re: This is why you don't buy cheap multimeters.

Ahh the hFE function reserved for only the bottom of the barrel models .

It's such a dead giveaway of a cheapie I don't know why they don't just ditch that useless function.

I'll admit my first meter was a tiny one like that (no hFE though ) branded by Radioshack but the probes were integral with the meter and the whole thing had an integral case.

Eventually from the probes being crammed into the case they too broke where they entered the probe handles. It used an annoying proprietary battery too.

Can't recall the battery designation code it's the type where if you cut it open you'll get a bunch of LR44 button batteries in series from it.

I'm all for using these on DC and unpowered circuits if you can't afford a decent and safe one. But I want a good meter in my hand I can trust. With HRC fuses, input protection, and a thick case with blast shields inside in case something goes wrong when I'm measuring live AC.

[tom66]

Re: This is why you don't buy cheap multimeters.

I was fairly impressed with one of my Mastech cheapies I owned for about two years. It even survived being set on ohms on 230V; the display readout was nonsense but it wasn't damaged. Unfortunately, when changing it's battery, I shorted an LDO and fried the main ASIC . Ah well, it was only £20...

[retiredcaps]

Re: This is why you don't buy cheap multimeters.

My DT830B blew up,

Mine thankfully, in retrospect, didn't work.

https://www.badcaps.net/forum/showpo...4&postcount=25

I have totally changed my mind since that post and now have an used Fluke 75, Fluke 12, Amprobe AM60, and gave away an Amprobe 15XP.

I almost had 2 RMS multimeters for less than $10, but someone sniped me at the end when I wasn't home.

PS. I saw your thread on eevblog regarding this subject matter.

[tom66]

Re: This is why you don't buy cheap multimeters.

My DT830B blew up, rather spectacular. Hole in the plastic case, charred PCB, not quite sure what went up!

Still, I keep one or two cheap meters, for testing low voltage circuits. Wouldn't even go near it with anything higher than 50V, the wire feels so flimsy and the probes are crap.

I have a BK 2709B but that stays mostly at home, not always around me when repairing things.

[larrymoencurly]

Re: This is why you don't buy cheap multimeters.

I switched to needle-sharp stainless steel probes because chrome plated brass probes kept telling me that 120VAC outlets had 0V, even though I thought I had scraped the probes hard enough to supposedly clean the oxide and make good contact.

BTW the test probes sold by the company behind www.TestLeads.com may not look like they're stainless any more because they're now chrome plated stainless.

[momaka]

Re: This is why you don't buy cheap multimeters.

The TaiwanBreakDownComponents company version I used to have did 5 ohms. It only lasted about a year before the pins at the end of the probes broke off.

Oh yeah, the probes on mine broke as well long time ago. Basically the wires pulled out of the probes' handles. Since these are the cheap type of probes that have the tips heat-pressed into the plastic, there really was no easy way of opening them and getting them fixed - or so you'd think. Of course, me being the cheap ass I am, I did fix them; just cut the plastic on the handles just a few mm from the tip, run the wire through the handle again, solder it back on the tip, and then finally hot glue everything back together.
Almost CAT IV compliant .

[c_hegge]

Re: This is why you don't buy cheap multimeters.

I have a cheap HongKongFlyApart, LLC 830B variant (that's actually my only multimeter, lol), and when I short-circuit the probes on the 2000 Ohm setting, it shows 3 Ohms . New batteries will bring it down to 1 or 2 Ohms, but it's not worth it. So when I get 3 Ohms in a circuit on that setting, I know it's a short-circuit .

The TaiwanBreakDownComponents company version I used to have did 5 ohms. It only lasted about a year before the pins at the end of the probes broke off.

[Krankshaft]

Re: This is why you don't buy cheap multimeters.

Someone had way too much time on their hands.

Geez the least they could do was use insulated wire instead of what I hope is enameled wrapping wire.

[Th3_uN1Qu3]

Re: This is why you don't buy cheap multimeters.

ICL7106 may be damaged by static electricity, transplant procedure is possible:

http://www.crystalradio.cn/bbs/thread-109673-1-3.html
http://www.crystalradio.cn/bbs/attac...UB9PB5bP14.jpg

Someone had way too much time on their hands.

I have a cheap HongKongFlyApart, LLC 830B variant (that's actually my only multimeter, lol), and when I short-circuit the probes on the 2000 Ohm setting, it shows 3 Ohms . New batteries will bring it down to 1 or 2 Ohms, but it's not worth it. So when I get 3 Ohms in a circuit on that setting, I know it's a short-circuit .

This is normal for the 830B and part of it is due to the crummy probes it comes with. With good probes it should read 0.6 to 0.9 ohms when shorted. I like my UT70A. It shows 0.0.

[lti]

Re: This is why you don't buy cheap multimeters.

My Harbor Freight $3 multimeter is more accurate in the resistance ranges than the old Danameter I normally use. That Danameter thinks a 220Ω resistor that measures at exactly 220 ohms on every other multimeter is actually only 170 ohms.

Also, the battery that came with the Harbor Freight meter sucked. The battery drained itself with no load on it at all. I can connect it to a 15V power supply and it will draw almost no current. It can not even power an LED placed directly across its terminals.