Long Term Reliability of Some Cheap Multimeters? - Page 1
Forum section: electronics / testgear

author: vinlove
author_rank: Frequent Contributor
timestamp: July 29, 2019, 06:43:33 am
content: I saw this on youtube, and thought it was a bit disputable.Are more expensive multimeters more reliable? Is it always the price which reflects the reliability? What about the way they are being used?

author: MosherIV
author_rank: Super Contributor
timestamp: July 29, 2019, 07:12:44 am
content: Hi, yes agree with Kerry in his video.I have a very old DT830 DMM. Still works but the dial switch is very loose now.Makes reading readings a real gamble, just not what you need when diagnosing problems.On the other hand I got a used Fluke 187. I did not realise how battered it was from the pictures when I bought it. The input jacks were reported as broken, how bad or had hard can it be repairing that I thought.The dmm front panel would not stay on!Anyway, after repairing the jacks and case, it still works perfectly.So, yes my experience matches what Kerry is saying : cheap dmms, the mechanicals are cheap and nasty, may wear out or just break.

author: bd139
author_rank: Super Contributor
timestamp: July 29, 2019, 08:31:02 am
content: Yeah I've had several cheapies and they usually are crap in the long term. The killer is mostly calibration drift and mechanical failure. The worst I had was a UT61E which drifted so badly it was useless. Then the rotary switch went on it.I like to compare cheap ones to this 87 I got recently. 20 years old, display knackered, jacks knackered. Hard life for a DMM:Cleaned it up, replaced the jacks and cleaned the zebra strips and the damn thing worked perfectly and was spot on cal against my 2018 cal 87V!That's quality. And it cost about the same as a new UT61E to me. No cal or mechanical problems other than they physical abuse it took!

author: vinlove
author_rank: Frequent Contributor
timestamp: July 29, 2019, 09:12:04 am
content: I have 4-5 cheap DMMs bought recently, and 2 of them are a few year ago, and they all seem working OK for now.One of them has problem, that when selecting ohms capacitance diode and continuity, it takes about 10 sec. to change over. But it was like that from the day I bought it. Because of that fault, I wanted to return it for refund, but seller refunded and asked me to keep it.The oldest DMM I have is a Fluke 25, and it is from early 1980s. It is size of big brick, and weighs like one too. But it still works perfect, and display is solid.If cheap DSOs are made with flimsy parts, and develops those reliability issues sooner or later, that's quite serious issues, because they tend to cost at least over 200£ even the cheapest ones. Hence why I went for the Rigol DS1052E for the proven reliability from long history of the model even with lesser spec.

author: bd139
author_rank: Super Contributor
timestamp: July 29, 2019, 09:16:49 am
content: Agreed. The really cheap DSOs are a terribly false economy. I'd rather have an older TDS220 than one of them if I was spending under £200

author: Mr. Scram
author_rank: Super Contributor
timestamp: July 29, 2019, 09:20:05 am
content: Reliability is what the Fluke brand name is built on. Being able to beat on a meter and being fairly sure the calibration is still decent after many years is what people pay for. That and the ability to handle gross overloads safely of course.

author: Kleinstein
author_rank: Super Contributor
timestamp: July 29, 2019, 09:35:58 am
content: Even big band meters can have long term issues - less likely than with the cheap brands, but the difference is not that significant. It's a general problem that it is hard to judge quality upfront. Even with good intents thinks like ROM-rot or overheating hybrids happened.The bigger problem with many of the cheap meters are possible safety flaws. It may be a little better in the EU (going after fake CAT ratings and taking products off the market), but it still is a problem.Judging from just one broken meter is also difficult, unless one can trace back the fault to a design flaw.

author: CDaniel
author_rank: Frequent Contributor
timestamp: July 29, 2019, 10:24:15 am
content: If you just look at the switch quality there is a big difference between a cheap and expensive multimeter ... as espected , so don't be naive to think there is nothing significant . Maybe if you use the multimeter once per month ...Cheap multimeters go to garbage , you don't hear stories about being repaired like a Fluke for example

author: Fungus
author_rank: Super Contributor
timestamp: July 29, 2019, 11:00:52 am
content: Quote from: CDaniel on July 29, 2019, 10:24:15 amThat doesn't mean theycan'tbe repaired. Joe Smith has repaired several cheap meters after zapping them in his robustness testing thread.

author: vinlove
author_rank: Frequent Contributor
timestamp: July 29, 2019, 11:34:39 am
content: I am sure the cheap meters could be repaired, but they must be not bothering to repair them? Just throwing them away when go wrong, and buying new?

author: bd139
author_rank: Super Contributor
timestamp: July 29, 2019, 11:42:43 am
content: I've repaired a couple of cheap ones. In fact when I got something from ebay a while ago, someone used some broken NIB Tenma meters as box padding (!) so I figured I'd try and repair at least one. These were DT830 based by the looks. The manufacturing flaws were just horrible so they got tossed.So yeah you can repair them but why bother?

author: joeqsmith
author_rank: Super Contributor
timestamp: July 29, 2019, 11:55:33 am
content: Quote from: Fungus on July 29, 2019, 11:00:52 amMost of these meters were electrically damaged and it's been a very small percentage that could be economically repaired.I attempted to life cycle a few meter's rotary switches and in some cases, there was nothing left to repair. Picture of an ANENG, where the cheap Fluke 17B+ still looked new after this same abuse.I am not sure cheap is the right word. I have some expensive poor quality meters that are not very impressive and some very low cost ones that are damn impressive. Iwouldn'tcall any Keysight product cheap but seeing their detent spring crack all four prongs after a few thousand cycles was less than impressive.

author: Fungus
author_rank: Super Contributor
timestamp: July 29, 2019, 12:11:54 pm
content: Quote from: joeqsmith on July 29, 2019, 11:55:33 amI'm sure you meant "wouldn't" but yeah, Keysight's multimeters seem like junk to me. Between OLED screens that fade to grey and detent springs that turn to dust, it doesn't seem like any of them are going to last much more than the warranty period. That makes them very expensive indeed.Flukes are overpriced compared to Brymens but at least you can make the argument that they're going to last a lifetime so you're only really paying $10-$20 a year for that 87V. Not so Keysight.

author: vinlove
author_rank: Frequent Contributor
timestamp: July 29, 2019, 12:21:36 pm
content: I am planning to repair one of my Analogue meters. Its' 0 ohms adjustment is non functional, and reading is not accurate at all.I am thinking it is something to do with potentio meter / variable resistor gone bad, and will try to troubleshoot, and replace them if faults parts are located.It is not a vintage analogue meter, but had it for about 10 years bought from Amazon. It is a Mastech 7040 or something like that. I have 3x Analogue MMs.One from 1950s post office one, the 7040 and cheap chinese MM called MF47. I like analogue MMs too.

author: EEVblog
author_rank: Unknown
timestamp: July 29, 2019, 12:29:56 pm
content: I have cheap DMM's from the 80's that still work fine.You can argue that quality brands like Fluke have built their reputation on being reliable, but then you have the explain the Fluke 19 which famously failed in countless numbers. If there is still a working one then it's pretty rare.All the brands have had issues over the years.Even if you have one model that has a good reputation, that can vary at any time due to batch issues.

author: EEVblog
author_rank: Unknown
timestamp: July 29, 2019, 12:33:11 pm
content: Quote from: bd139 on July 29, 2019, 09:16:49 amA TDS220 survived this

author: Mr. Scram
author_rank: Super Contributor
timestamp: July 29, 2019, 12:34:28 pm
content: Quote from: EEVblog on July 29, 2019, 12:29:56 pmI guess that model was a fluke.A big difference often is support and the willingness to fix problems. We've seen various issues with Keysight kit on this forum in the past, but they've ultimately taken measures to fix those issues often swapping out used equipment for brand new items.

author: Fungus
author_rank: Super Contributor
timestamp: July 29, 2019, 12:46:23 pm
content: Quote from: Mr. Scram on July 29, 2019, 12:34:28 pmFlukes were never "cheap"?I'm guessing "Radio Shack"

author: Mr. Scram
author_rank: Super Contributor
timestamp: July 29, 2019, 12:50:42 pm
content: Quote from: Fungus on July 29, 2019, 12:46:23 pmIt helps if you read beyond the first line.

author: Mechatrommer
author_rank: Super Contributor
timestamp: July 29, 2019, 01:04:54 pm
content: my Uni-T UT71A bought less than $100 is still working 9 years now. i dont detect any drift that makes it unusable etc, its still my main DMM, except the tilt bail has been broken long time ago so sometime its inconvenient on the bench. i wont call those cheapy as false economy. if i have to buy them again, i will do so no hesitation, i also bought 3 cheapies afterward and 1 converted to bench format. all still working fine. the 1 or 2 that failed during my history are bought locally and they are like super crap cheapy among the cheapy $5 like royal crapness. but then i think my next upgrade will be Fluke 87V, there's many used unit in ebay for $400 and less. the reason simply because i never have a quality brand DMM before, if everybody can get a hold of it, so why cant me?

author: CDaniel
author_rank: Frequent Contributor
timestamp: July 29, 2019, 01:18:25 pm
content: Many years ago the quality gap wasn't that significant ... but I think the topic question is about what you can buy today .

author: joeqsmith
author_rank: Super Contributor
timestamp: July 29, 2019, 01:40:45 pm
content: Quote from: Fungus on July 29, 2019, 12:11:54 pmGood catch, corrected. A few people have posted pictures of the rubber coating they use falling off. Some of them really look bad after a few years.Here, getting a Fluke serviced I expect would be much easier than having a Brymen serviced. For me, this isn't a big deal but for a larger corporation, service can be very important and worth the added cost.I came across another old Fluke that I had planned on buying for the case and a good switch wiper contact. I looked in really good condition, but sadly the thing worked.I have vowed, no more 189s..I am still planning to put the 121GW through it's paces. We are coming up on the second year as I continue to wait for a version without the need of a shim and other changes. Starting to wonder if we will ever see it in the wild.

author: bd139
author_rank: Super Contributor
timestamp: July 29, 2019, 01:47:31 pm
content: That was one thing that got my about the BM867s. I asked my local calibration place for a quote and they wouldn't calibrate it. Same with the GW Instek. Fluke/Keysight - yeah no problems. Annoying. Not sure you can get Brymen parts anywhere either. When I did the 87 mentioned earlier, I got the input jack assembly from TME in Poland zero problems at all.

author: schmitt trigger
author_rank: Super Contributor
timestamp: July 29, 2019, 02:18:37 pm
content: All companies make mistakes. Regardless of what they manufacture or service they sell.No matter how good they are, a company is still an imperfect human endeavor.The difference between a "good" company and a "bad" one, is that the good company will move quickly to address the mistakes, make an effort to remediate the customers, and apply the lessons learned to future products or services.My personal experience: When Compaq computer still existed, I purchased a top-of-the-line laptop for my daughter, which was studying architecture. Architectural 3D rendering programs require a lot of resources.Long story short: the laptop would severely overheat. I contacted Compaq, who told me that I could either get a full refund or they could air ship a replacement one. Two days later we got the brand new computer, and a prepaid shipping box to return the old one. There was even a phone number to call, for UPS to pick it up at home, if I could not drop it at an UPS center. The replacement laptop worked flawlessly for many years.A short while later, Compaq was acquired by HP and we know how it all went.

author: tinhead
author_rank: Super Contributor
timestamp: July 29, 2019, 02:19:11 pm
content: i bougt once Protek 506, nearly 25yrs ago, for a student at that time was ok. It does still works within it's specs (when i calibrate it from time to time). Sure, the range switch is really hard working - by design, but still ok. It is not anymore everyday DMM, but still in use.

author: EEVblog
author_rank: Unknown
timestamp: July 29, 2019, 02:29:02 pm
content: Quote from: tinhead on July 29, 2019, 02:19:11 pmThat range switch is the hardest one I've ever felt. Crazy force required to turn it.

author: joeqsmith
author_rank: Super Contributor
timestamp: July 29, 2019, 02:30:37 pm
content: Quote from: bd139 on July 29, 2019, 01:47:31 pmJust so we are clear, you were not asking them to align it, but calibrate it? Really odd if it was just for calibration as our cal house will cal about anything.I had asked Brymen to provide the alignment procedure for the BM869s but I haven't provided it to the cal house to see what they thought as the two meters havn't really moved (considering the abuse I put them through, I'm a bit surprised).

author: tinhead
author_rank: Super Contributor
timestamp: July 29, 2019, 02:41:35 pm
content: Quote from: EEVblog on July 29, 2019, 02:29:02 pmindeed, but i remember as i tested it at that time, i thought "it feels like a solid design"

author: bd139
author_rank: Super Contributor
timestamp: July 29, 2019, 02:45:23 pm
content: Quote from: joeqsmith on July 29, 2019, 02:30:37 pmSorry full calibration and alignment. I was evaluating cost of ownership of BM867s over Fluke 87V.I kept the Fluke in the end because it was less hassle in this department, smaller, the backlight wasnt a perpetual dick and user interface is way better.

author: Kleinstein
author_rank: Super Contributor
timestamp: July 29, 2019, 05:22:21 pm
content: I still have and use an old "Voltcraft" 3.5 digit DMMs - though repaired once. Not very cheap, but still relatively cheap some 30 years ago.The 35+ year old cheap Russian made analog multimeter is also still alive (2 repairs) - probably not comparable to today's cheap parts anyway and the price may not have reflected true costs. The old analog meter also need some care, as they don't have the full protection one is used today (e.g. no fuse and very little protection for Ohms).Cheap DMMs have the calibration problem: even if they can be calibrated, the cost may be higher than for a new one. New ones may not come with enough calibration documentation to use them in some commercial uses at all.