Hioki DT4222 Compact TRMS Multimeter teardown - Page 1
Forum section: electronics / testgear

author: bluey
author_rank: Regular Contributor
timestamp: June 02, 2020, 02:43:43 am
content: Dave reviewed the bigger brother DT4256.https://www.eevblog.com/forum/blog/eevblog-973-hioki-multimeter-review-clamp-meter-teardown/The DT4222 (and similar sized DT4221, DT4223, DT4224) uses the same Hioki HAZ01 DMM IC, but omits current ranges to get the size down.https://www.eevblog.com/forum/blog/eevblog-973-hioki-multimeter-review-clamp-meter-teardown/msg3078647/#msg3078647Runs on a single 1.5V AAA battery. NiMH battery is specifically allowed, but the battery indicator will behave differently.Got one as a second meter since they are currently half price athttps://www.testequipmentonline.com.au/.I hardly ever use the current ranges, since I'm mostly using the multimeter for troubleshooting and repairs.Performance is very similar to the DT4256 (6000 count updates 5x/sec TRMS), with slightly reduced accuracy from running on 1.5V. Basic DCV accuracy of DT4256 is 0.3%+/-3. For DT4222 it is 0.5%+/5 and Hioki guarantees accuracy for 12 months.

author: bluey
author_rank: Regular Contributor
timestamp: June 02, 2020, 02:49:16 am
content: One metal thread insert screw for battery cover. Four self tappers into plastic (PPE). Access to calibration contacts via battery cover.

author: bluey
author_rank: Regular Contributor
timestamp: June 02, 2020, 02:52:56 am
content: Two metal thread screws with captive spring washer from PCB to lead connecting pins in rear case. The large PCB hole for the range switch and the spline connection seem a mechanical step up from the DT4256 and DT4282.

author: bluey
author_rank: Regular Contributor
timestamp: June 02, 2020, 02:55:29 am
content: PCB upper and lower parts closer up. Inside rear case.

author: bluey
author_rank: Regular Contributor
timestamp: June 02, 2020, 02:56:59 am
content: SW version 1.01. LCDs self test mode.

author: bluey
author_rank: Regular Contributor
timestamp: June 02, 2020, 02:58:21 am
content: Reassembled.

author: bluey
author_rank: Regular Contributor
timestamp: June 02, 2020, 06:01:29 am
content: Couldn't read all the part numbers, so disassembled again to take more pics. Bottom end.Surge suppressor CSB-242M.http://www.yds.co.jp/product-e/ecsb%20series.html

author: bluey
author_rank: Regular Contributor
timestamp: June 02, 2020, 06:02:47 am
content: Top end close ups. Now having been able to read most of the part numbers I'm none the wiser.After rereading Hioki’s HAZ01 white paper, the last pic shows the 5.12 MHz crystal oscillator.

author: bluey
author_rank: Regular Contributor
timestamp: June 04, 2020, 04:36:58 am
content: Detachable leads have 2.2 mm pin recessed in the rear of the body and a socket in the lead sleeve (8mm OD). I've never really liked the idea of fixed soldered leads on pocket sized DMMs.Looking to see if I can find a suitable connector for DIY optional leads for electronics. Hioki only does the direct replacement leads plus tip attachments for long pin and alligator clips.

author: bluey
author_rank: Regular Contributor
timestamp: June 06, 2020, 12:38:22 am
content: New Hioki DT4222 vs 1991 Fluke 87-I running "8.4V NiMH" never been adjusted:a. Hioki with supplied alkaline battery - reading same as Flukeb and c. Hioki with Eneloop NiMH - reads 1-3 counts higher with lower voltage supply