Tonghui LCR meter teardown, is BK879B just a rebranded meter?

[Wartex]

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 Instek


Protek


Mastech


Unknown


There 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.

[zaoka]

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?

[Wartex]

The 10 KHz light-grey color $200 Tonghui is absolutely identical inside to $400 Protek from Mouser.com


Check this out

[Wartex]

Escort mutations

[nukie]

Actually those power supplies reminds me a lot of made in England/Canada - Sorensen/Xantrex power supplies.

[tinhead]

Actually those power supplies reminds me a lot of made in England/Canada - Sorensen/Xantrex power supplies.

to 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 will
not 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 one
or 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 to
buy used known manufacturers model (like Xanterx), if you have luck you will get one with GPIB/RS232 for same price.

[Wartex]

Xantrex is like Extech - some stuff is genuine, some is rebadged chinese stuff.

[tinhead]

Xantrex is like Extech - some stuff is genuine, some is rebadged chinese stuff.

Xantrex 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).

[saturation]

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.

The 10 KHz light-grey color $200 Tonghui is absolutely identical inside to $400 Protek from Mouser.com


Check this out

[Wartex]

I GOT IT!!!!

UPDATE: I got the Tonghui 100 KHz PCB picture thanks to David at http://www.novarex.com

I asked BK about Tonghui and BK similarities, this was their response:

B&K Precision is the manufacturer of the 878B and 879B and has been the industry leader in the handheld LCR meter category for more than 10 years, whereas Agilent entered this market very recently. Regarding similar models you may come across, we feel that imitation is the sincerest form of flattery. While we do not have a 100 kHz version currently available in the 87xB series, we are currently working on developing one (no release date available). We are looking into the possibility of extending our line and may be adding a 100 kHz or similar model.

This 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!

[nukie]

I have a feeling that TH makes them where as BK bought them and simply rebadged.

[Wartex]

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.

[zaoka]

BK has always been rebranding stuff. I remember their old CRT rejuvenators, it was made by Konig, Germany.

[zaoka]

Where did you find TH2822C  for half of the price of BK879?

[Wartex]

Where did you find TH2822C  for half of the price of BK879?

2822C 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.

[saturation]

The new Agilent LCR meters are released today and surprisingly, it looks very much like the top end 100kHz Tonghui!

[Mechatrommer]

either lazy to design new shape, or want to cut cost on existing design.

[Wartex]

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.

[Wartex]

Confirmed, Agilent 100 KHz looks nothing like BK or Tonghui

[shadowless]

can you post some photo?

[nukie]

Yup, anymore info on that? I am itching to get my paws on one...

[EEVblog]

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..

Correct. 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.

[shadowless]

For a while i thought i won't be needing an inductance meter but i was wrong.  Hope it get reviewed soon.