Tonghui LCR meter teardown, is BK879B just a rebranded meter? - Page 1
Forum section: electronics / testgear

author: Wartex
author_rank: Frequent Contributor
timestamp: June 08, 2011, 12:28:10 am
content: For the lazy:BK879B is on the left, TH2822C on the right. Find the difference.I've seen several members mention they used THxxxx LCR meters, could anyone post pictures of the insides? Everywhere I look - Protek, Agilent, BK - they look like rebadged Tonghui and not the other way around - the buttons, the LCD screen, the specs are identical and always one step behind.Before you call me crazy, lets look at some "brand" name power supplies:Tektronix:GW InstekProtekMastechUnknownThere is a BK Precision version of this as well and about a dozen others. The other day I witnessed a guy pay close to $500 for one of those.The originator for these PSUs is Mastech, I found after much research. All the major brands blatantly ripped off the design, switched some minor components around, rebadged it and voila. Trust me, the $150 Mastech is in no way worse power supply than $400 Agilent. They are exact same. I want to buy a quality LCR meter but don't want to pay $340 for BK Precision that is a copy of a $150 Tonghui. This "rebadging" is driving me nuts.

author: zaoka
author_rank: Frequent Contributor
timestamp: June 08, 2011, 02:21:26 am
content: We had this discusion already as far as I remember.LCR meters are formerly Escort designs that has been upgraded by different companies and they just look the same from outside.BK meter looks completly different inside than Agilent etc..Tonghui meters cost: TH2822 is 175usd, for TH2822A is 210usd and for TH2822C is 420usd directly from them + shipping.I bought new cheap (old design) Tonghui on eBay (around $99), it was not accurate when measuring large capacitors (comparing to Sencore LC103 and Fluke meters), I returned and got refund.For power supply I have that one, its GW Instek. Got it of eBay for $120 long time ago, its with analog meters. The only compain I have is that plastic mask on the front, it cracked. They could use metal front mask because its very heavy.So far it works perfect and meters are very accurate. Its got relays inside... I can take it a part and make some pictures if you want to see?

author: Wartex
author_rank: Frequent Contributor
timestamp: June 08, 2011, 03:23:51 am
content: The 10 KHz light-grey color $200 Tonghui is absolutely identical inside to $400 Protek from Mouser.comCheck this out

author: Wartex
author_rank: Frequent Contributor
timestamp: June 08, 2011, 04:15:00 am
content: Escort mutations

author: nukie
author_rank: Frequent Contributor
timestamp: June 09, 2011, 03:02:50 am
content: Actually those power supplies reminds me a lot of made in England/Canada - Sorensen/Xantrex power supplies.

author: tinhead
author_rank: Super Contributor
timestamp: June 09, 2011, 12:34:19 pm
content: Quote from: nukie on June 09, 2011, 03:02:50 amto clone one of the simple Xantrex/Sorensen models is a easy job, there is nothing special inside (except a good transformer).The problem starts with the more complex models or with addon boards like GPIB, therefore you willnot find many cheap lab power sup. with such extras.The majority is just simple standard circuit with a cheap transformer, too small heatsink,undersized transistors and "savings" everywhere like for example two pots instead of multiturn oneor very simple voltage reference instead of high precision.If you start to replace these parts such power supply will costs much more, sometimes is cheaper and smart tobuy used known manufacturers model (like Xanterx), if you have luck you will get one with GPIB/RS232 for same price.

author: Wartex
author_rank: Frequent Contributor
timestamp: June 09, 2011, 10:13:22 pm
content: Xantrex is like Extech - some stuff is genuine, some is rebadged chinese stuff.

author: tinhead
author_rank: Super Contributor
timestamp: June 10, 2011, 07:57:41 pm
content: Quote from: Wartex on June 09, 2011, 10:13:22 pmXantrex started to produce lab power supplies long before people in china got electricity!The whole power supply line has been sold long time ago, currently Elgar/Ametek/Sorensen are producing them,however inside is still the same technology (except GPIB controllers which of course changed over the time).

author: saturation
author_rank: Super Contributor
timestamp: June 11, 2011, 03:04:20 pm
content: When Agilent releases its new LCR HH meters in the next few weeks, the price range is ~ identical to Tonghui, so at the worse if yo choose Agilent's you'll have their service and documentation quality for the same money you'll spend on the top line Tonghui.Quote from: Wartex on June 08, 2011, 03:23:51 am

author: Wartex
author_rank: Frequent Contributor
timestamp: June 12, 2011, 03:02:55 pm
content: I GOT IT!!!!UPDATE: I got the Tonghui 100 KHz PCB picture thanks to David athttp://www.novarex.comI asked BK about Tonghui and BK similarities, this was their response:QuoteThis is Tonghui TH2822C:This is BK879b vs TH2822C (notice missing components on BK):Eat my ass BK Precision! "has been the industry leader" my ass. Tonghui predates BK meters, so guess who ripped off who's design!

author: nukie
author_rank: Frequent Contributor
timestamp: June 12, 2011, 03:11:05 pm
content: I have a feeling that TH makes them where as BK bought them and simply rebadged.

author: Wartex
author_rank: Frequent Contributor
timestamp: June 12, 2011, 09:52:25 pm
content: I can now buy Tonghui for 1/2 the price of BK Precision knowing the components are exact same. I bet the firmware is the same across 10KHz models (bk879b and th2822B) too.

author: zaoka
author_rank: Frequent Contributor
timestamp: June 14, 2011, 12:55:32 pm
content: BK has always been rebranding stuff. I remember their old CRT rejuvenators, it was made by Konig, Germany.

author: zaoka
author_rank: Frequent Contributor
timestamp: June 14, 2011, 12:57:44 pm
content: Where did you find TH2822C for half of the price of BK879?

author: Wartex
author_rank: Frequent Contributor
timestamp: June 14, 2011, 09:24:59 pm
content: Quote from: zaoka on June 14, 2011, 12:57:44 pm2822C is NOT an equivalent of BK879, it has much higher specs than BK.The TH2822B is a direct equivalent and can be had for as low as $180 USD. BK879B is 300-400 USD depending where you buy.

author: saturation
author_rank: Super Contributor
timestamp: June 14, 2011, 09:39:00 pm
content: The new Agilent LCR meters are released today and surprisingly, it looks very much like the top end 100kHz Tonghui!

author: Mechatrommer
author_rank: Super Contributor
timestamp: June 14, 2011, 10:56:46 pm
content: either lazy to design new shape, or want to cut cost on existing design.

author: Wartex
author_rank: Frequent Contributor
timestamp: June 14, 2011, 11:48:52 pm
content: The agilent is 20k count, and tonghui is 40k count. However, Agilent is $60 cheaper. Also, agilent says "Low battery indicator will appear when voltage drops below ~7.2 V" - pretty bad. I'm pretty sure agilent looks nothing like TH or BK precision. Contrary to what BK guy told me on youtube, I believe Agilent makes their own stuff while BK is just rebadging chinese stuff.Can't wait to see it inside.

author: Wartex
author_rank: Frequent Contributor
timestamp: August 04, 2011, 04:30:19 am
content: Confirmed, Agilent 100 KHz looks nothing like BK or Tonghui

author: shadowless
author_rank: Regular Contributor
timestamp: August 06, 2011, 03:20:08 pm
content: can you post some photo?

author: nukie
author_rank: Frequent Contributor
timestamp: August 07, 2011, 11:15:25 pm
content: Yup, anymore info on that? I am itching to get my paws on one...

author: EEVblog
author_rank: Unknown
timestamp: August 08, 2011, 08:08:58 am
content: Quote from: zaoka on June 08, 2011, 02:21:26 amCorrect. Many LCR meters used to come from the same Escort design.When Agilent bought Escort a few years back, they severed those ties and everyone else was on their own. Although the others still had rights to the original design and could still sell it and improve it etc.I was told by Agilent that the latest model LCR meter is a new Agilent design.They promised to send me one for review, but haven't.Dave.

author: shadowless
author_rank: Regular Contributor
timestamp: August 09, 2011, 12:46:47 am
content: For a while i thought i won't be needing an inductance meter but i was wrong. Hope it get reviewed soon.