This is why you don't buy cheap multimeters.

[Th3_uN1Qu3]

As you know i own a number of meters for different purposes. The Uni-T UT60E and UT70A do the heavy lifting, but i often need a couple extra basic meters. One of them is a DT838 i bought this summer IIRC. I mainly bought it for the temperature and buzzer, as i already had two 830Bs.

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 thought it was the battery so i replaced it today. Surprise surprise - exact same behavior. To make matters worse, the temperature range is busted too. It still measures voltages fine, but that's what i didn't need it for. On the other hand my two 830Bs still work great even though i've had them for years... but those two are both brand name (one Uni-T, one Mastech), while the 838 was the HongKongFlyApart, LLC version. But hey, it's only five bucks.

[KeriJane]

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

Did you open it up and check for BAD CAPS?

Sounds like a great opportunity expand your skills into multimeter repair or at least to expand your parts collection....

[Th3_uN1Qu3]

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

Yes i did open it up, it only has a few SMD ceramic caps and a MKT 100 nF and that's it. They test good. Sounds more like a resistor that has shifted value, and they can't be measured in-circuit. For a $5 meter it isn't worth my time. I'll buy a $20 meter from Uni-T to replace it, as i currently have an extra temperature probe which i can't use on anything. To make matters worse the ICL7106 is in epoxied blob form, and it doesn't even respect the standard pinout. Too many cut corners to bother with it.

[b700029]

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

[momaka]

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 .

On the 200 Ohm scale, it shows 0.9 to 2.7 Ohms, depending on how it feels. Most of the time, it's over 2 Ohms.

Continuity/diode test shows pretty much the same numbers as the 2000 Ohm scale when the numbers get low.

That multimeter has served me well for many repairs, though, so I will dismiss its flaws for now .

[SparkeyJim]

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

Hello. My name is Jim and I go by the user name SparkeyJim. I am new to the forum. I am currently working on LCD and plasma televisions and would like some input. What cap meter or LCR meters would you recommend for smd and mini alum caps on these sets.
Many thanks to those that respond. I will respond in kind.
Thank you, Jim G

[kc8adu]

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

i noticed the accuracy slides on the cheap hf meters just before the low batt indicator comes on.they are still fine for the shop help kid,ect.he blows it up i toss it and pull another from the backstock.critical stuff i use the old beckman manual range unit that we got rechargeable 9v's for as it does not even have auto off.or my fluke 77.

[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.

[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.

[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.

[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.

[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 .

[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.

[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.

[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.

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...

[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.

[ratdude747]

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

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

[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).

[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.