HIOKI 3522 LCR Meter teardown - Page 1
Forum section: electronics / testgear

author: Michel95200
author_rank: Newbie
timestamp: December 04, 2018, 08:39:36 am
content: HelloHioki 3522 100kHz LCR meter uses traditionnal autobalancing technique with undersampling ADC. Main parts are:* OPA2134 + BUF634 for transimpedance amplifier* 5 range resistors selectable with relays TQ2-5V* voltage and current range amplifiers use OPA2134 and NJU201 analog switches* test signal generator uses AD9831A DDS* test voltage level: multiplying DAC AD7945* output buffer : BUF634* measurements are performed using 16-bits ADC ADS7809U with undersampling technique* undersampling clock uses another DDS IC AD9831A

author: ogden
author_rank: Super Contributor
timestamp: December 04, 2018, 08:28:12 pm
content: Nice job! What was motivation to reverse engineer schematics of this module? Any further plans? BTW you could increase contrast of pictures.

author: _Wim_
author_rank: Super Contributor
timestamp: December 04, 2018, 09:39:42 pm
content: Wow, very nice job. That must have been quite a bit of work!

author: Michel95200
author_rank: Newbie
timestamp: December 04, 2018, 10:03:03 pm
content: I am independant and for a part of my job I am an electronic designer for a well known european instrumentation company. For this work I make sometimes this kind of reverse engineering to see the technique used by competitors and the parts they use. I did the same for other LCR meters if some are interrested. It took me half a day to draw the complete schematic of this one. I would like to find a not working Keysight E4980A or the analog board only do to the same.

author: dr.diesel
author_rank: Super Contributor
timestamp: December 04, 2018, 10:04:52 pm
content: Quote from: Michel95200 on December 04, 2018, 10:03:03 pmVery interested! Hameg?

author: ogden
author_rank: Super Contributor
timestamp: December 04, 2018, 10:14:47 pm
content: Quote from: Michel95200 on December 04, 2018, 10:03:03 pmMany would be interested. Please create new thread for each instrument in question.QuoteImpressive skills. Do you use some specific "reversing know how" or just useful tips you can share to us?

author: DaJMasta
author_rank: Super Contributor
timestamp: December 04, 2018, 10:23:45 pm
content: I've got a 3532-50 meter and while it uses a lot of the same parts, it's got more of everything! Three DACs, a dual channel audio ADC, another few range switches (two different kinds of relays, most like the ones on your board), and long, long chains of filtering opamps. Haven't done any proper reverse engineering, but despite the differences it's neat to see a lot of similar parts.

author: Michel95200
author_rank: Newbie
timestamp: December 04, 2018, 10:49:16 pm
content: Generally modern LCR meters use dual ADC to sample voltage and current at the same time. In the 3522 voltage and current are sampled sequentially.In the Hioki 3531 I have also reverse-engineered the ADC is a dual audio ADC AK5389 from Asahi Kasei. This instrument is very interresting, it uses also undersampling technique with external fast sample and hold. For high frequency band it uses a reconstruction of the current using demodulation of the error and reconstruction of the current using sine/cosine signals coming from two DDS. Schematic is more complicated than the 3522. Maybe the 3532-50 is similar, do you have a picture of the main board ?

author: DaJMasta
author_rank: Super Contributor
timestamp: December 05, 2018, 12:24:47 am
content: I have some mediocre quality diagnostic picturesA similar technique may also be used in this one, if I remember right, the signal on either input of the ADC was a 1kHz sine of some description, regardless of the frequencies I tried... though I don't 100% remember. I believe the SO16 chips around the ADC are all analog muxes, and the lines of 4 SO8 packages are single opamps, I believe fairly high spec but not too much GBP given the operating frequency of the device. There's also a bit more on the board under the digital board which isn't pictured - at least one extra trail of filtering amps, which would be under the bottom left portion of the full pic of the board. You can see the input/output terminals on the left side of the two images that show the frontend stuff.

author: Michel95200
author_rank: Newbie
timestamp: December 05, 2018, 08:48:55 am
content: Hioki 3532 seems technically closed to the 3531. It uses a reconstruction technique using demodulators/modulators. I cannot see the reference of these parts, in the 3531 classic MC1496D are used. Three DDS are present, one for sine/cosine generator and another one for undersampling clock generation. The sample and hold circuits seems identical (the area with blue through hole capacitors). I have delimited the different functional blocks.

author: DaJMasta
author_rank: Super Contributor
timestamp: December 05, 2018, 05:55:16 pm
content: Very interesting! Those suspected MC1496Ds are actually just more DG411DYs, but there very well could be that section under the digital board in an area not pictured by these pics. I remember being a little baffled when looking over it, so it's sort of nice to hear that it uses a fairly complex measurement schemeI remember being real surprised to find local regulation in the form of 78XX and 79XX regulators in those larger all-plastic TO-220 style cases. I suspect they use some more modern variant with better stability and PSRR, but I hadn't really considered them as good regulator choices for high sensitivity analog sections.

author: ogden
author_rank: Super Contributor
timestamp: December 05, 2018, 11:11:54 pm
content: Quote from: DaJMasta on December 05, 2018, 05:55:16 pmTwo pairs of DDS+LM361 are strong hint that indeed it is IQ (sin/cos) mixer system and they use DG411DY as mixer (demodulator).Quote from: Michel95200 on December 05, 2018, 08:48:55 amCould you share it's schematics?QuoteThird DDS (ic202) looks like test signal going to Hcur. I don't know how legit that seller and his offer is, but look atthose piles of LCR meters!

author: hoangduongo
author_rank: Newbie
timestamp: April 16, 2019, 03:44:17 am
content: Hello,It might not be totally related. but does anyone here have the schematic of the Hioki 9268/9269 DC bias modules that go with the 3522 LCR meter?At the very least, the basic principle and feasible working plan will also be much appreciated, as I am fancy to imitate one for my 3522.Thanks a lot!Duong

author: coromonadalix
author_rank: Super Contributor
timestamp: April 16, 2019, 09:36:00 am
content: you have Hioki 3522 on EbayEven low as 4xx$ usd dollars for partsThis seller has many of them ??https://www.ebay.com/itm/Used-Hioki-HIOKI-3522-50LCR-1Pcs/173558354050?hash=item2868e25082:g:0QQAAOSwtM1brCao

author: hoangduongo
author_rank: Newbie
timestamp: April 17, 2019, 06:58:30 am
content: Coromonadalix,I don't think I fully understand your question.I already have the 3522 meter (purchased from a local factory liquidation), now I'm looking to copy/build the DC bias modules (like the 9268/9269), as the ones appear on ebay are even more expensive than what I paid for my 3522.Thanks, Duong

author: coromonadalix
author_rank: Super Contributor
timestamp: April 17, 2019, 10:11:56 am
content: Ill correct my post, you have many 3522 on Ebay, and one seller link seems to have ton's of them ?? they sell around 1k$$ usdThe lcd seems expensive ?Is it a good lcrI tried to build an dc biais board for an Fluke 6304 i had, i had the chance to copy the 6306 dc biais board from an eevblog member, but the same parts used where very difficult to get, 150$ in parts only, no pcb madethks

author: hoangduongo
author_rank: Newbie
timestamp: April 17, 2019, 04:49:53 pm
content: Hi,Imho, the 3522 is a decent meter, especially for me who works with audio most of the time. But also because of that I frequently need to measure chokes/transformer with DC current passing through, which then leads to the demand of the DC bias modules (the 9269 DC current module is preferred for this reason).I looked up and found your project with the 6304 meter and 9565 module, looks terrific but I'm not sure if they use the same principle with the Hioki.Thanks

author: xu59
author_rank: Newbie
timestamp: March 26, 2024, 04:19:00 am
content: 朋友们好！哪位能告诉我如何进入日置3532-50数字电桥的的校准界面。不胜感谢！

author: KungFuJosh
author_rank: Super Contributor
timestamp: September 11, 2024, 12:40:01 am
content: Quote from: xu59 on March 26, 2024, 04:19:00 amMe too! Has anybody figured out how to get into calibration for the 3532-50 or similar?Thanks,Josh

author: KungFuJosh
author_rank: Super Contributor
timestamp: September 20, 2024, 08:13:25 pm
content: Quote from: Michel95200 on December 05, 2018, 08:48:55 amDo you still have your 3532? I'm curious what in-circuit resistance readings you get for the group of resistors around R361.Thanks,Josh