New Zoyi multimeter+oscilloscopes - ZT-70xS, up to 50MHz/250MSps (nov 2022)

[Altair8800]

Anyone who owns a ZT-702S or ZT-Z03S or Aneng AOS02, or Aneng AOS03

Here is a 3D stand that works better than the built-in stand.  I've printed this out a month ago and tested it.  Also, it is nice that they have spots/slots to put your DMM Probes and Oscilloscope Probes.

https://makerworld.com/en/models/1401325-aneng-aos03-stand#profileId-1453352

I was going to make my own stand but accidently came across this.  Assume most might not know about it because it is hard to search on because it is named after the Aneng AOS03 which is not as common as the ZT-703S or 702S

PS:  Do not have access to a 3D printer, besides family/friends sometimes Libraries might have a Maker Lab, maybe you can print it there...

Cheers

[surenz]

I removed the built-in leg as when installed and not stretched it makes the multimeter wobbly. I don't get how they omitted this obvious defect. For use in standing position this 3d model ofc is far more convenient.

[cncjerry]

Would a couple of you please test your meter(s) by trying to measure AC on a DC value of 15V?  I have one supply that on 15V, the AC should be displayed as 20mv, but my 703 jumps all over the place and never gives a good reading.  My Agilent DMM (of course) and even my FNIRSI (not even attempting to spell that correctly) both measure around 20mv.

Thanks

[tol]

Would a couple of you please test your meter(s) by trying to measure AC on a DC value of 15V?

[GnatGoSplat]

Would a couple of you please test your meter(s) by trying to measure AC on a DC value of 15V?  I have one supply that on 15V, the AC should be displayed as 20mv, but my 703 jumps all over the place and never gives a good reading.  My Agilent DMM (of course) and even my FNIRSI (not even attempting to spell that correctly) both measure around 20mv.

Mine jumps around.  Stays 0, but the decimal moves, then it flashes 5-something for a split second, repeats.  My Fnirsi reads about 340mV while my vintage Tenma reads about 250mV.

[noemi]

If anyone is missing Format menu item on newer firmware version (>1.3.9) please check Apps -> Image Viewer -> F1
Format should be an option under F3 button

[xfint34]

Would a couple of you please test your meter(s) by trying to measure AC on a DC value of 15V?  I have one supply that on 15V, the AC should be displayed as 20mv, but my 703 jumps all over the place and never gives a good reading.  My Agilent DMM (of course) and even my FNIRSI (not even attempting to spell that correctly) both measure around 20mv.

Thanks

Same behavior on mine. Same also on Aneng AN8007 and OWON CM2100. Trying to measure AC on a DC supply never settles.

[Aldo22]

Would a couple of you please test your meter(s) by trying to measure AC on a DC value of 15V?

What is the frequency of the AC signal?
Or is it simply noise?  In that case, the TRMS DMM cannot do much with it.

[neosunrise]

I did some tests with a 19V DC laptop power adapter as I don’t have a 15V DC handy. My 703s presented the same behavior and it jumped all the time. My UT-61e presented the same behavior. I also tested it with my two Fluke 87s and both were able to show around 20mV in the AC range, although the last digit jumped back and forth and never settled.

I hope this helps.

Would a couple of you please test your meter(s) by trying to measure AC on a DC value of 15V?  I have one supply that on 15V, the AC should be displayed as 20mv, but my 703 jumps all over the place and never gives a good reading.  My Agilent DMM (of course) and even my FNIRSI (not even attempting to spell that correctly) both measure around 20mv.

Thanks

[cncjerry]

AC is US 60hz. all my other meters read it correctly as 20 to 23 mv.  This is the first significant error I've found on an otherwise great meter.  This is a common function as well. Everybody checks AC riding on a DC supply.

[Aldo22]

ZT-225 displays the value stably in AC/DC mode, but only with 10mVAC precision.
Nevertheless, it is a good indicator that there is a small AC component. Otherwise, it is really 00.00.

In pure AC mode, auto ranging does not work with 10VDC offset and 20mVrms ripple.
You have to select the range manually, then it is stable and accurate.

[Mortymore]

Would a couple of you please test your meter(s) by trying to measure AC on a DC value of 15V?

I used a signal generator set for 60Hz, 56.6mVpp (20mVac), ~10Vdc
The OWON HDS242 in multimeter mode was jumping allover in AC Autorange. If set for 200mV range it measured fine.
The other meters (OWON HDS160, FLuke 83;75, Iso-tec IDM505;507) didn't had any problem measuring the 20mVac in autorange mode.

[cncjerry]

Thanks to everyone who took the time to measure. Clearly setting it to a fixed range probably would solve the problem, and I'll test that tonight.

Thanks again

Edit: testing with manual range solved the problem.

[surenz]

At least one thing fixed with this multimeter lol:



Now charges up to 4.2 V (checked already).

[zenon]

Was the thermal pad soldered of the original IC?

[surenz]

Yes, it was. Btw the charging current is above 1.1A so it's mandatory to solder this pad. The chip itself does not heat too much but the inductor next to it goes hot.
The link to Aliexpress product: https://www.aliexpress.com/item/1005010452531322.html

[Faeren]

At least one thing fixed with this multimeter lol:

(Attachment Link)

Now charges up to 4.2 V (checked already).

This is a defect on the 703S?

[surenz]

Yes, it is.
The chip they used charges the 18650 battery up to 4.35V. At least they used protected cells so it theoretically should not charge more than 4.20V but for peace of mind and because it's cheap I ordered the correct chips and changed it.
You will probably need a hot air gun to desolder and solder back the new chip.
More info in this topic: https://www.eevblog.com/forum/testgear/zoyi-zotek-zt-703s-fire-hazard-while-charging/

[xKertx]

Was the thermal pad soldered of the original IC?

It is also a ground pad. The chip wont work without it.

[Skander]

New product in the series - ZT-700 (no DMM). It isn't on their Chinese or English websites yet, but it's being sold on the official AliExpress store: https://aliexpress.com/item/1005011753712706.html

[tunk]

New product in the series - ZT-700 (no DMM).

Maybe this warrants a new and separate thread?
The price seems high (US$50-55) - the ZT-701 has similar specs
and costs US$35-40, and the Zeeweii DSO1C81 has better specs
(80MHz/250MSpS) and costs US$40-50.

[tunk]

There's also an "upgrade model" ZT-703S+ of the 703S:
- 50 MHZ, 2ch, 280MSpS
- 10ns/div - 20s/div
- 20mV/div - 10V/div
- up to 128kByte record length
- signal generator, sine 10MHz, square/triangle/half/full 2MHz, sawtooth 200kHz
- DMM 25000 count
- screen 3.5"
- size 177x89x40mm, 380g, 3400mAh battery
Not obvious what the "upgrade" is (maybe they have "optimized" the hardware?).

Currently US$119 on eBay:
https://www.ebay.com/itm/177912574579

[Skander]

There's also an "upgrade model" ZT-703S+ of the 703S:
- 50 MHZ, 2ch, 280MSpS
- 10ns/div - 20s/div
- 20mV/div - 10V/div
- up to 128kByte record length
- signal generator, sine 10MHz, square/triangle/half/full 2MHz, sawtooth 200kHz
- DMM 25000 count
- screen 3.5"
- size 177x89x40mm, 380g, 3400mAh battery
Not obvious what the "upgrade" is (maybe they have "optimized" the hardware?).

Currently US$119 on eBay:
https://www.ebay.com/itm/177912574579

It has the V.F.C. markings in some of the renders, which matches what they previously leaked on their new year video as the "ZT-706s".
Perhaps they decided to rebrand it 703s+, which kinda makes sense since the specs are pretty much identical in terms of bandwidth etc.

It's on their second Ali store: https://aliexpress.com/item/1005011766989646.html

The only other 'improvement' is the slightly higher bandwidth on the signal gen, but nothing else. Still the same clunky overclock for high/normal modes etc.
Not worth looking into pretty much, just a Rev 2 of the 703.

Edit: official comparison:

[abozkurt]

Hi everyone,
Is there anyone who can adjust the time in automatic shutdown mode?
I set the time to any value, even when I turn it off, it shuts down in 30 seconds. Has anyone found a solution?
Version: 1.6.12

[zenon]

See if it doesn't fix after a reset.