IWATSU VOAC22 DMM Teardown - Page 1
Forum section: electronics / testgear

author: mettlerr
author_rank: Unknown
timestamp: March 29, 2016, 03:11:40 am
content: Hello allI'm new to this forum, and I thought I will start with my first post being a teardown of a new DMM I've just received today: It's aIWATSU VOAC22Digital Multimeter. It's only available for the Japanese market, and being a Swiss expat in Japan, I thought I get one, as my SANWA CD771 isn't that great.It's a logging DMM, and it also has that neat red covers of the A jacks on the front, which retract when you put the range switch into the A range. But the quite positive overall impression stops there unfortunately... Or my know-how is just not good enough to appreciate it (being a beginner), so please feel free to correct me.The specs of the DMM can be found here (in Japanese, but I guess the most important data is readable anyway):http://www.iti.iwatsu.co.jp/ja/products/voac/voac22_spec.htmlBeing a quite reputable brand here in Japan, I thought I get a good DMM from IWATSU, especially for that price (55'000 JPY, around 490 USD). But I must say, I am quite a bit disappointed about the build quality for the price. See following pictures for what I mean:Here is what comes with the package (no temperature sensor included, that's extra):Back side with battery cover removed (fuse access is nice):Infrared communications port cover removed on the top back of the unit:Opened up, first view of the board (note the input jacks which are soldered directly to the board and the minimal slotting on the board for protection):Detailed view of the board's backside:Board's front (note the feeble split input jacks they've used):Detailed view of the front of the board:I didn't bother removing the shielding, as it's soldered directly to the board, so no view of the processor used, sorry guys. All in all the build quality is dismal for the price! I would have expected quite a bit more input protection, solid input jacks and an overall better build quality... Guess it's back to FLUKE for me.Oh, and the display is a joke. Here it is compared to the SANWA CD771:It's really hard to read that thing. And no, it's not the batteries. I've exchanged them with freshly bought ones, and the display stays the same. I also can't regulate contrast anywhere in the menu, so also no help there (or I just couldn't find it yet).Also, that DMM is HEAVY, with a feeble stand to boot.

author: mos6502
author_rank: Frequent Contributor
timestamp: March 29, 2016, 03:39:07 am
content: They used neon bulbs for the backlight? How retro.

author: Vgkid
author_rank: Super Contributor
timestamp: March 29, 2016, 04:22:22 am
content: ^^^ nope gdt for protection, most likely.Nice unit, to bad about the display.

author: mos6502
author_rank: Frequent Contributor
timestamp: March 29, 2016, 04:38:14 am
content: Quote from: Vgkid on March 29, 2016, 04:22:22 amQuote from: Vgkid on March 29, 2016, 04:22:22 amDat AD780A:http://www.analog.com/media/en/technical-documentation/data-sheets/AD780.pdf0.03% ...Too bad the PCB looks really cheap. Those unrouted edges, ugh.

author: retiredcaps
author_rank: Super Contributor
timestamp: March 29, 2016, 04:49:36 am
content: Quote from: mettlerr on March 29, 2016, 03:11:40 amWelcome. Thanks for sharing the pictures. It looks identical to Yokogawa TY720.http://tmi.yokogawa.com/products/portable-and-bench-instruments/digital-multimeters/ty720-digital-multimeter/

author: crispy_tofu
author_rank: Super Contributor
timestamp: March 29, 2016, 04:51:40 am
content: Wow, that thing really chews up batteries, 4 AAs for 120 hours...

author: mettlerr
author_rank: Unknown
timestamp: March 29, 2016, 05:01:43 am
content: Quote from: retiredcaps on March 29, 2016, 04:49:36 amThank you retiredcaps. I wonder who is actually building it for whom... IWATSU for Yokogawa or the other way around.

author: zaoka
author_rank: Frequent Contributor
timestamp: March 29, 2016, 12:12:19 pm
content: There is the same Kyoritsy 1062 model with different colors... on theflyer it appears it has better display, however, its thanks to photoshopYou could get HIOKI meter for that price...

author: mos6502
author_rank: Frequent Contributor
timestamp: March 29, 2016, 12:16:29 pm
content: Quote from: zaoka on March 29, 2016, 12:12:19 pmOr, you know, a Fluke 87V.

author: Wytnucls
author_rank: Super Contributor
timestamp: March 29, 2016, 12:31:29 pm
content: Quote from: mettlerr on March 29, 2016, 05:01:43 amYokogawa is the OEM manufacturer for Iwatsu and some of Kyoritsu portable DMMs.

author: mettlerr
author_rank: Unknown
timestamp: March 29, 2016, 12:35:47 pm
content: Quote from: Wytnucls on March 29, 2016, 12:31:29 pmAh, I see. Thanks Wytnucls! Well, my Fluke 87V is already on the way. I had a look at the HIOKI DMMs and a teardown here in the forum, and they seem to be well worth a shot. Maybe getting one of those later too. I don't seem to be able to stop "collecting" DMMs....