A True Killer-Meter: JCD-(un)branded ANENG AN8002 variant with USB charging - Page 1
Forum section: electronics / testgear

author: Cymaphore
author_rank: Regular Contributor
timestamp: June 21, 2021, 11:33:47 am
content: Hi,while I was searching on eBay for a bag for equipment, I accidentially stumbled upon this marble. It was only 12,90 € so I could not resist to get it (product offer see here).It seemingly is basically an ANENG AN8002 variant with Micro-USB jack for charging and a funny designed rotary switch. Package includes a nice bag, convertible ANENG test leads, a garbage screwdriver, temperature probe and a micro USB charging cable, as seen on the picture.The USB charging jack is not insulated, so beware, it's truly akiller meter! :-) ...Unlike the pictures from the eBay product page, it doesn't contain any JCD-branding on itself or the bag. I also was unable to find any information about it anywhere. No manual included in my delivery.From my first impressions it measures accurately and looks like a decent electronics meter. All the functions present seem to work quite well and testing against my reference gave perfect readings. USB charging seems to work, it doesn't attempt data handshake on that port.I had to greese the rotary, out of the box it was almost unusable (hard to turn and sticky), but now it's fine.Funny thing.Anyone has seen this one before or has the actual specs for it? eBay page specs are obviously wrong, it's 6000 counts, not 9999.Best regards,Martin

author: ebclr
author_rank: Super Contributor
timestamp: June 21, 2021, 11:43:25 am
content: This is a decent meterhttps://www.fluke.com/en/product/electrical-testing/digital-multimeters/fluke-87vThe one you post, it's barely a meter

author: tunk
author_rank: Super Contributor
timestamp: June 21, 2021, 12:11:29 pm
content: Looks a bit like this:https://lygte-info.dk/review/DMMAnengM10%20UK.htmlMaybe you could open it and compare.

author: Cymaphore
author_rank: Regular Contributor
timestamp: June 21, 2021, 12:49:31 pm
content: Quote from: tunk on June 21, 2021, 12:11:29 pmThanks for the hint, I attached an image of the PCB.Based on that specs and rotary switch labeling it looks almost identical, except that this unit I have provides an output voltage of 4V for diode testing.But except the same LCD, battery holder and probe jacks, the PCB looks very different.Quote from: ebclr on June 21, 2021, 11:43:25 amFor sure you say this now. But who will be the laughting stock when new year is coming or 4th of july or whatever and you're all out of fireworks. You think your precious F87 will help you then? My firecracker here will not fail me, for sure.I only got it out of pure curiosoty as a toy. I wanted to see the magic insulated USB charging connector by myself. :-)

author: Fungus
author_rank: Super Contributor
timestamp: June 21, 2021, 09:04:08 pm
content: Quote from: Cymaphore on June 21, 2021, 11:33:47 amThat doesn't mean it isn't isolated.Is it really for charging? I don't see why these meters would need to be rechargeable.Quote from: Cymaphore on June 21, 2021, 12:49:31 pmNo rechargeable batteries there. I'm guessing it's more likely to be a comms port.

author: AVGresponding
author_rank: Super Contributor
timestamp: June 22, 2021, 12:05:47 am
content: Quote from: Fungus on June 21, 2021, 09:04:08 pmIt's got rechargeable cells in it, and looking at the traces the only ones you can see seem to go through a diode to a voltage reg IC and an inductor maybe to the ground plane, and the OP says it charges. Also the OP did say there's no comms handshake. There's certainly no obvious optoisolators, trace gaps, or isolation slotsLooks sketchy af to me.

author: Cymaphore
author_rank: Regular Contributor
timestamp: June 22, 2021, 12:10:26 am
content: Quote from: Fungus on June 21, 2021, 09:04:08 pmUSB 0V goes to BAT 0VUSB +5V is passing a Si-Diode and one transistor/regulator, then going to BAT +3VUSB D- and USB D+ could be traced nowhere and look unsolderedUSB Shield reads 18kOhm against DMM GND and COM inputUSB Shield reads 10MOhm against V and A inputSo, if I would be mad and hook it up against the live wire on COM, there would be a chance to trip the RCD by touching the USB port :-)Quote from: Fungus on June 21, 2021, 09:04:08 pmWith two ok-ish NiMH cells (2.67V combined):Rotary in OFF position, USB connected, I read a charging current of 2.8mA on the batteries.Rotary in V position, USB disconnected, I read a current draw of 1.6mA on the batteries.Rotary in V position, USB connected, I read a charging current of 1.2mA on the batteries.It even works without batteries only powered via USB.On an empty pack (2V combined) it provides a charging current of about 200mA.It tried to charge empty alkaline batteries as well. :-)Quote from: Fungus on June 21, 2021, 09:04:08 pmI hoped so somehow, might be interesting to play around with. But it's a standard chinese suizide charging port.Such an interesting device... Removed branding, standard SMD DMM Chip, no COB... Chip has it's labeling removed obviously via laser or CNC cutting, very precise.What an unusual thing.My guess, looks like someone designed it to make use of existing AN8001/8002 production line equipment with a new PCB, but then the customer refused it, so they dumped the series 0 production on the marked or something. Standard SMD DMM-Chip with high-effort removal of the labeling seems very unusual for this kind of a garbage device.PCB has on the back the label"WM16A/B/C2019-OCT-21FR4 REV:00"Also the accuracy of the readings in V and Ohms is interestingly extremely good compared with the BM789 and the MM12, but I don't know if this is normal for ANENG or whoever makes these things.

author: sleemanj
author_rank: Super Contributor
timestamp: June 22, 2021, 12:43:21 am
content: Love how the call it a "USB Multimeter" when the only thing even remotely USB in it is the socket.You can never have too many cheap multimeters though, always room for one more.