East Tester/Mustool ET4410 LCR meter - first impressions - Page 1
Forum section: electronics / testgear

author: JohanH
author_rank: Frequent Contributor
timestamp: May 08, 2023, 01:06:49 pm
content: These are currently on Banggood with quite cheap shipping to EU. At the time, the East Tester wasn't available (don't know if it was a glitch, but the site didn't let me buy it), so I bought the Mustool branded one. But I'm sure they are exactly the same.A few Youtubers have reviewed these and there are also older posts in the forum about them, but I thought to put up some pictures for reference.This is the 100 kHz model and I'd like to point out a few things and ask some questions about things that haven't been really clear in reviews and forum posts.The meter is delivered with basic shielded Kelvin clips that do their job, nothing fancy. The BNC connectors on the cable are of the type where the metal sleeve tends to unscrew itself when you attach and detach the cable. You can tighten the sleeves carefully (but don't twist the cable).If you have your own shielded Kelvin cables, the BNC connectors on the front panel are grounded, or you can use the separate ground terminal.There is an English paper manual provided with good description of basic functions. Some details differ from an earlier manual that I downloaded from the East Tester site. So possibly an updated revision?The manufacturer also provides a document with SCPI commands (from the East Tester home page). There are RS232 and USB ports on the back panel. Unfortunately no Ethernet.Chassis is made of steel and aluminium, so it provides good shielding.They provide two extra fuses, F0.5A 250V. There is only one fuse in the IEC socket.The inside of the meter looks like the earlier pictures/videos shown of these. The transformer screws are glued (good). You can see that the transformer is bent down a bit, probably due to forces during shipping. I just bent it up a bit again. The power cable to the front button is shielded (a nice detail) with one end attached to chassis ground. I did move the power cable to the side of the chassis and tied it to the foot of the transformer. I do like that it's a real old school on-off mains switch. There is plenty of space if you wanted to change the IEC connector to one with a filter. Ground connection is visually OK.Calibration is a two-step process. Open the clips (or attach the clips to some non-conductive material) and push CAL for a few seconds. The meter will count down. After it's ready, short the clips together and press CAL again. The meter will detect if clips are open or shorted.I'm a bit unsure about some of the functions. E.g. it seems like the Electrolytic Capacitor function is kind of a preset with a set voltage level (1V) and bias (1.5V). At least I interpret it that way. So I wonder if it's preferred to measure all polarized capacitors in this mode?The DC Resistance mode disables Level and Frequency while Bias is set to 1.5V. The manual says to use this mode to measure DC resistance of coils and transformers. There seems to be some loss of accuracy compared to the regular measurement function (according to specifications). I understand that by using DC to measure, you will only get the resistance component. But I'm not sure of the details. Is the regular method not measuring DC resistance accurately when it comes to coils and transformers?Edit. Answering myself here about the DCR mode. Due to parasitic impedance in coils, transformers and possibly wirewound resistors, at higher frequencies AC resistance measurement might be affected. So that's why they recommend using DCR mode to test DC resistance of coils and transformers in the manual. Some reviewers of the ET4401/4410 mentioned that the DCR mode is for testing resistors or resistance, but that's not entirely correct. The regular AC measurement mode seems to have higher accuracy, so for generic resistance measurement, I would use that and only use DCR mode for cases where parasitic effects would matter. That's my conclusion, but I could be wrong.

author: mawyatt
author_rank: Super Contributor
timestamp: May 08, 2023, 02:37:44 pm
content: Would be interesting to see the schematics and what components are utilized.Regarding the DC Bias on the capacitor readings, this might be to keep the instantaneous AC signal across the DUT from going negative. With a 1VPP AC signal and a 1.5VDC Bias the AC signal would swing from a low of +1V to a high of +2V across the DUT, without the DC Bias the signal would swing from -0.5 to +0.5V.Best,

author: JohanH
author_rank: Frequent Contributor
timestamp: May 08, 2023, 03:37:13 pm
content: Quote from: mawyatt on May 08, 2023, 02:37:44 pmI don't think schematics are available.Martin72 began to reverse engineer the meter here (I see that you were part of the discussion, but will reference it also for other member's benefit):https://www.eevblog.com/forum/testgear/east-tester-et4410-esr-measure/msg4331890/#msg4331890Quote from: mawyatt on May 08, 2023, 02:37:44 pmYes, makes sense for measuring polarized capacitors.

author: JohanH
author_rank: Frequent Contributor
timestamp: May 08, 2023, 03:54:41 pm
content: Martin72's meter is revision "ET44.M.V1.31 2020.11.27" (link to his pictures), whereas mine is "ET44.M.V1.6 2021.11.18". One difference is some beefy GDTs for input protection in the newer revision.