Tonghui Bench multimeter - Page 1
Forum section: electronics / general

author: Zensei
author_rank: Contributor
timestamp: September 01, 2011, 07:31:33 pm
content: Hello all.I'm in the market for an entry level, but high accuracy multimeter. I purchased a UNI-T UT804, which will arrive tomorrow.But I'm thinking that there must be something a bit better out there.Does anyone here own a Tonghui bench multimeter or know anything about thequality build of their devices? I'm also looking for pictures of the inside.Or if you guys know of a good quality meter at an affordable price (around 400 USD max.) I would very much appreciate any pointersHere's one I'm considering:http://www.pinsonne-elektronik.de/pi9/pd73.htmlThanks, Kasper

author: Bored@Work
author_rank: Super Contributor
timestamp: September 01, 2011, 08:56:15 pm
content: Tonghuin and their bench multimeter are kind of a mystery. You will find people arguing that Tonghui is a "good" company because of their LCR meters which were (or were not) rebranded by other companies. But they only give nine years of company history on their web page, and are suspiciously silent about how they were founded.The thing is their (exaggerated?) history of LCD meters says nothing about their bench multimeters. The TH1941 is on the market for a few years now, but I am not aware of anyone having done a serious review of one. I haven't even seen any dubious review. It is almost as if no one buys them. Which can't be, or they won't produce them any more. There is even one company that looks as if they sell a rebadged version of the meter as VA80http://www.mastech.com.cn/html/en/products-va80.htmThe specs and features of the TH1941 are nice - on paper. As a bench meter fan I did consider buying one in the past, but ... Asian companies are known to be very generous when it comes to their meter specifications. So I refrained from adding one to my collection. Unless someone really opens a TH1941 there is no way to predict if there is a chance the meter meets its specification. And unless someone does some serious measurements with calibration equipment such a visual inspection of a meter can only bring you so far.The reason people buy brands is not that these are necessarily better value for money, but not the least because brand multimeters (usually) don't come with these uncertainty.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: September 01, 2011, 09:17:50 pm
content: Welcome Kasper.The price looks tempting on the German link.But the specific seller lives in a very small town, and his business size must be small too.Other than the thought about trusting Tonghui, it must be and a second thought like : if you are trusting this small retailer for your warranty coverage.Do you ?

author: Mechatrommer
author_rank: Super Contributor
timestamp: September 02, 2011, 12:34:18 am
content: Quote from: Zensei on September 01, 2011, 07:31:33 pmsomeone accurately made a teardown of the uni-t bench meter...basically, its a handheld dmm in a big casing with the needed power supply circuitry. more space for storing stuffs. here is his post...https://www.eevblog.com/forum/index.php?topic=1331.msg17865#msg17865

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: September 02, 2011, 02:14:35 am
content: Quote from: Mechatrommer on September 02, 2011, 12:34:18 amIf you manage to power it up with AA batteries, UNI-T will hire you .Large LCD displays needs lots of food.

author: Mechatrommer
author_rank: Super Contributor
timestamp: September 02, 2011, 04:05:40 am
content: Quote from: Kiriakos-GR on September 02, 2011, 02:14:35 amQuote from: Mechatrommer on September 02, 2011, 12:34:18 amand if its still not enough, you can put some banana inside. (not banana plugs, but the banana the monkey usually eat)

author: Bored@Work
author_rank: Super Contributor
timestamp: September 02, 2011, 05:32:19 am
content: Quote from: Mechatrommer on September 02, 2011, 04:05:40 amA sandwich should fit fine into the UT-804's accessory storage compartment, too. Interestingly most vendors never show that it has this storage compartment, because then it would be obvious for buyers that there isn't much electronics in the meter. This vendor almost had the balls to show ithttp://laptopbattery2.com/images/UT804_U80_2.jpgBy the way, the UT-804 is right from the factory prepared to be powered from batteries (C cells). The battery compartment is right under the sandwich storage compartment, and can be reached from it.

author: Zensei
author_rank: Contributor
timestamp: September 02, 2011, 06:10:04 am
content: Boredatwork:I'm not planning to use it as a lunchboxI've been searching for Tonghui too and have just about nothing on them... Maybe I can have the pinsonne guy send me some pics of the insideMechatrommer:Yes, I have also seen the pictures of the empty box. I will test it for accuracy, though.Kiriakos-GR:The retailer may be from a small city, and it's an online store, so I choose to be naive and trust him for warrantyWe will see how that goes, if needed...If you had to recommend a good quality one, what should I look for? At a reasonable price, of course...

author: seb
author_rank: Newbie
timestamp: September 02, 2011, 08:32:48 am
content: it look like some Chinese withelable stuff.my advice for you is, spend your money into a used high quality bench top multimeter. search for a equipment reseller an look for some units from Rohde&Schwarz / Keithley / Schlumberger / Fluke / Kontron / HP Agilent / Datron / etc...don't waste you time into these Chinese stuff. I have searched some month for a cheap Chinese scope, and the result is : i will wait a few month to save more money and by a Agilent MSO.

author: Mechatrommer
author_rank: Super Contributor
timestamp: September 02, 2011, 09:45:25 am
content: Quote from: Zensei on September 02, 2011, 06:10:04 amyes pls do. and report it here. i was not saying uni-t is bad or good. i just said it has plenty of storing space. the person made the teardown didnt report the performance. and last time i was "window shopping" for lcr meter, the tonghui name came up. i saw their lab grade lcr bench meter, their handheld lcr with kelvin probe in ebay. and there's talking about their 100KHz lcr meter which other companies havent produced yet even agilent came up late with it. from info i gathered, no one can fault tonghui brand, and i have a sense they got some "seriousness" into measurement device and made their own R&D. but no one ever mentioned their bench meter here. if you got budget, you can be the first to make the review here, and most people will appreciate your effort.

author: Bored@Work
author_rank: Super Contributor
timestamp: September 02, 2011, 03:35:57 pm
content: Quote from: Zensei on September 02, 2011, 06:10:04 amWhy not? That is a noble cause.

author: Zensei
author_rank: Contributor
timestamp: September 02, 2011, 04:15:20 pm
content: I will do a review of it and compare the various meters I have. I actually have 4 Uni-T products, so it will be a good one for their products.I just need a good quality meter as a reference. I don't think using another Uni-T meter as a reference makes much senseA comparison chart with measurements would be fine, yes? If I have to make a video, it's gonna take forever, since I'm not skilled in videoediting...I would really like to check out the Tonghui, since there's so little information on it. It would help people in the same situation.

author: nukie
author_rank: Frequent Contributor
timestamp: September 04, 2011, 01:29:27 am
content: Uni T is very precise but its accuracy drift rapidly compared the yellow brand.

author: Zensei
author_rank: Contributor
timestamp: September 05, 2011, 07:38:16 pm
content: Latest update in my UT804 adventure:I received the meter on friday and my first impression was that I liked the design, even though it is a plastic meter, I like the size of it.The diplay is also very nice, great backlighting. The buttons and the switch knob are a bit small, but manageable.I started out testing different DC voltages and capacitance against my other meters. I don't have an AC generator, so I had to wait till Monday, when I got to school. I think I will not bother to publish the results, as the test was rather limited... I only got to test DC 2-45 V and capacitance.I have to say though that I feel the UT804 was the most reliable of the ones I tested against.I checked the PCB inside and it's a revised version, which is supposed to be more accurate than the first version.While testing the meter in amp mode, 230 v, with 3 other meters in series, the UT804 threw up on the bench. It started making a humming sound, which I thought came from the voltage source (the test was done in a High voltage lab). The display lid up the whole display and then it went dead.I was pulling 1,96 amps, so I didn't overload it. (Yes, I checked the fuses.)Too bad really, because I was actually considering keeping it. I mean, as long as the measurements are accurate, I don't really care if it sits in an empty case... But the build of it corresponds with the price, but for that price, you can't expect a Fluke.I will send it back tomorrow and get a Tonghui TH1942 instead.I wouldn't mind having the UT804, if it didn't fail like it did, but since it did, I'm gonna go for a Tonghui. Also, so I can do a review on that for the benefit of others looking for info on itFor the benifit of all, Zensei

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: September 05, 2011, 11:07:55 pm
content: Zensei , originally about a year back I was planing to get an UT804,and I stop thinking about it, as soon I gotaccidentally= long story,three old Fluke bench type DMM.Personally I do not see as adventure what happened in your end.The DMM that you got had a faulty part in the PSU.I had spot and repair even a problem in the Fluke 8050A related to the power supply.UNI-T has a nice video in their web page, they use exclusively Fluke calibrators,I would suggest to give to the UT804 and another chance.If I was interested for one bench type DMM today, the UT804 would be my first choice.

author: Zensei
author_rank: Contributor
timestamp: September 08, 2011, 09:39:09 am
content: I already sent it back... The seller told that there had been problems with UT804 in the past. The Tonghui is much faster and better quality. At least that's what the seller told me. It's not that I didn't like UT804. But, with it having problems, I want to check out the Tonghui as well and make a review for everyone's benefit.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: September 08, 2011, 12:40:16 pm
content: I do not know how the sellers act in your country, but in my they give a positive feedback to any company that they have largest profit from selling their products.You are actually the first in this forum who reports such an event.Tonghui does not belong in the list of my trusted brands, but if you plan to start reviewing things,the best practice is to use them first for a month at list.

author: nukie
author_rank: Frequent Contributor
timestamp: September 09, 2011, 12:44:56 pm
content: By posting these information, I don't mean to encourage or discourage anyone to go out and buy one of these TH meters. There are lots meters that has proven themselves on the market such as the HP Agilent/Keithley meters. I took the liberty of internet and information to cut and paste these pictures from Chinese electronics forum. This is the Tonghui TH1961.Bench meter of this class like the HP 34401/10A, Keithley 2000, Fluke 8846A all utilize a special selected variant of LM399. The TH1961 has a off the shelf LM399 as base voltage reference.From here is base on my very own observation. The parts selection and build quality just doesn't cut it. Picture 3, R35 - The use of low cost decade resistor divider(it's actually just some normal through hole resistors packed in epoxy case) is going to have a large drift overtime. You're better off sourcing a popular bench meter of this class second hand or used at the same price. Used meters are much more stable and lower drifting. Buy a name brand meter, most calibration labs will be able to calibrate it especially with these software based calibration.Of course this TH is miles ahead of the UniT lunch box.

author: saturation
author_rank: Super Contributor
timestamp: September 09, 2011, 02:30:47 pm
content: Thanks for these. Google has the price over $700, for a few hundred more you can get a new Agilent 34401 or 10A, or a used one for less than $400, then send it to Agilent for refurbishing as needed. Likewise for the less accurate meters in Th lineup, there are Agilent bench meters equally competitive in price vs the lineup.

author: Bored@Work
author_rank: Super Contributor
timestamp: September 09, 2011, 04:57:51 pm
content: I understand it is their flagship bench meter, three times more expensive than the TH1941.Judging from the pictures only, I would say Tonghui at least made an hones attempt with this TH1961. Although the copying, e.g of the front plate, is funny.

author: Joshua
author_rank: Regular Contributor
timestamp: September 09, 2011, 11:08:25 pm
content: For 400 usd why not get a fluke 87v?

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: September 10, 2011, 12:42:44 am
content: Quote from: Joshua on September 09, 2011, 11:08:25 pmDo not go in there ..The bad Wolf called Agilent U1272A and currently is under discount to 230 $ or near there.The bench type DMM is a different animal, and I like them too.

author: Zensei
author_rank: Contributor
timestamp: September 16, 2011, 08:53:40 am
content: @Nukie,Thanks for the pictures! I have ordered the TH1942 model and a UNI-T UT71E handheld meter. Will do a tear down review of them both and post it in a new thread, when it arrives.Hopefully be next weekend...Zensei

author: grenert
author_rank: Frequent Contributor
timestamp: September 16, 2011, 04:53:42 pm
content: Wow, you must be a martyr! Why get an unknown bench meter when you could get a low-range brand name like the Agilent U3401A for only $450? Well, at least everyone will learn something from your purchaseThanks for offering to take 'em apart for us.

author: Zensei
author_rank: Contributor
timestamp: September 19, 2011, 12:24:35 pm
content: @grenertYes, But I happen to live in the most expensive and heavily taxed country in the world, so 450$ is not possible for me.AND I also do it to get the information out there on these products. So that someone looking for info can find something on them.So, I guess I am a martyr... Lol