Author Topic: A True Killer-Meter: JCD-(un)branded ANENG AN8002 variant with USB charging  (Read 601 times)

0 Members and 1 Guest are viewing this topic.

Offline Cymaphore

  • Regular Contributor
  • *
  • Posts: 72
  • Country: de
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 a killer 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
« Last Edit: June 21, 2021, 11:36:09 am by Cymaphore »
 

Offline ebclr

  • Super Contributor
  • ***
  • Posts: 2256
  • Country: 00
This is a decent meter

https://www.fluke.com/en/product/electrical-testing/digital-multimeters/fluke-87v

The one you post, it's barely a meter

 :-DD
 

Online tunk

  • Frequent Contributor
  • **
  • Posts: 433
  • Country: no
Looks a bit like this: https://lygte-info.dk/review/DMMAnengM10%20UK.html
Maybe you could open it and compare.
 

Offline Cymaphore

  • Regular Contributor
  • *
  • Posts: 72
  • Country: de
Looks a bit like this: https://lygte-info.dk/review/DMMAnengM10%20UK.html
Maybe you could open it and compare.

Thanks 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.

This is a decent meter

https://www.fluke.com/en/product/electrical-testing/digital-multimeters/fluke-87v

The one you post, it's barely a meter

 :-DD

For 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. :-)
 

Offline Fungus

  • Super Contributor
  • ***
  • Posts: 12352
  • Country: 00
The USB charging jack is not insulated, so beware, it's truly a killer meter! :-) ...

That doesn't mean it isn't isolated.  :popcorn:

Is it really for charging? I don't see why these meters would need to be rechargeable.

Thanks for the hint, I attached an image of the PCB.

No rechargeable batteries there. I'm guessing it's more likely to be a comms port.
« Last Edit: June 21, 2021, 09:06:53 pm by Fungus »
 

Online AVGresponding

  • Super Contributor
  • ***
  • Posts: 2083
  • Country: england
  • Exploring Rabbit Holes Since The 1970s
The USB charging jack is not insulated, so beware, it's truly a killer meter! :-) ...

That doesn't mean it isn't isolated.  :popcorn:

Is it really for charging? I don't see why these meters would need to be rechargeable.

Thanks for the hint, I attached an image of the PCB.

No rechargeable batteries there. I'm guessing it's more likely to be a comms port.

It'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 slots

Looks sketchy af to me.
nuqDaq yuch Dapol?
Addiction count: Agilent-AVO-BlackStar-Brymen-Fluke-Hameg-HP-Keithley-IsoTech-Mastech-Megger-Micronta-Racal-Siglent-Solartron-Tektronix-Thurlby-Time Electronics-TTi-UniT
 
The following users thanked this post: Cymaphore

Offline Cymaphore

  • Regular Contributor
  • *
  • Posts: 72
  • Country: de
That doesn't mean it isn't isolated.  :popcorn:

USB 0V goes to BAT 0V
USB +5V is passing a Si-Diode and one transistor/regulator, then going to BAT +3V
USB D- and USB D+ could be traced nowhere and look unsoldered
USB Shield reads 18kOhm against DMM GND and COM input
USB Shield reads 10MOhm against V and A input

So, 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 :-)

Is it really for charging? I don't see why these meters would need to be rechargeable.

With 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. :-)

No rechargeable batteries there. I'm guessing it's more likely to be a comms port.

I 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/C
2019-OCT-21
FR4 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.
 

Offline sleemanj

  • Super Contributor
  • ***
  • Posts: 2712
  • Country: nz
  • Professional tightwad.
    • The electronics hobby components I sell.
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.
~~~
EEVBlog Members - get yourself 10% discount off all my electronic components for sale just use the Buy Direct links and use Coupon Code "eevblog" during checkout.  Shipping from New Zealand, international orders welcome :-)
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf