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

[tol]

I have noticed, if the signal is somewhat unstable at 100ns using both channels then pressing F3 (TRIG), will make  triggering become stable, but if you leave F3 for another function, the signal becomes unstable again. Also just selecting the blue channel in "Vol/Time" will make the signal stable

I have FW 1.6.4

This is a very strange version. If you catch the signal in normal mode in 50 us scale (and maybe others), hold it, and use cursors to measure the signal duration, it increases twice at your eyes and so do the measurements. For example, 100 us long signal shows and measures as 200 us signal!


Also, there are many other bugs, for example, if you catch the signal, it may look at the trigger correctly, but when you try to move it, the trigger changes its place unpredictably. At 2us long signals and 2us time scale, if you press CURSOR button to adjust cursors, the signal just disappears (actually goes far left beyond the screen). MOVE button has the same pitiful experience. This firmware is a garbage, I just wanted to measure the duration and the amplitude of my signal and I cannot do it... oh no, finally I could, but I wasted ~10 minutes for the task that can be completed in 30 seconds with a reliable oscilloscope

I installed ZOYI-703S-FW-V127.ZTK for comparison. There are many trigger issues as well, but you can't believe how fast it is in comparison with 158! I wish Zotek could make a new firmware without all that garbage in 158 that slows it down so horribly, just basic functionality, but reliable.

By the way, the shape of the signal is less neat in 127, which is probably closer to reality.

158 seems to spend some CPU time for various filtering and it slows it down noticeably. I think most users would rather prefer the true shape of the signal than filtered, but I think it deals with marketing more, they think if the [really ugly] signal will look neat, it will increase sales, but I don't agree with it..

[Majk]

Helllo All, I am lot sadisfied with my ZT-703S with old firmware cant go lower of 100 usec in Time/dev, updated firmware to 156 after reading here
that last firmware 164 very slow and lot of bugs. Any suggestion wich fw version is the besat for fast performance in mesurement and best bandwith. 10nsec Time/Dev
Now with fw 156 minimum Time/Dev is 10nsec need testing others functions.
How to eneter in the FFT mode ?

In attachment fimwares 119,121,127,128,129,132,135,138,139,142,155,156,157,163,164 in one zip file the version 164 is the last frtom official ZOYI site.

[tol]

Any suggestion wich fw version is the besat for fast performance in mesurement and best bandwith.

I tried something like 5 random versions starting from 1.27 and ending with the last version and was not satisfied with any of them. You can see the form of the signal but you cannot measure it correctly in many (all?) versions using the cursors or the grid in some zoom scales, it just shows wrong results and you never know when it shows correctly and when it lies. The problem is that there is no complete history file for firmware changes and we don't know what work was made in every version, it's difficult to understand how and when bugs appear and disappear. I think the only way for this device to become usable is to make the firmware open-source, so that professional programmers form all countries could revise it and fix all the bugs, but I'm sure Zoyi will not do it, they'd rather bury this device under tons of their bugs that they cannot fix.

BTW, I'm tired of waiting for a reliable firmware version, so I ordered DSO3D12 last week, I hope it will be better. Just for information, I use 1.42 now, this version is not so slow and horrible as the 1.5.x versions, but the measurements in some zoom levels seem to be also incorrect and there are trigger issues as well If you use this oscilloscope for some responsible work, I'd advice you to change it with something more reliable.

[Majk]

I will ask Zoyi for firmware logs changes this can help, its a pity that the mesurements are so no reliable.
Thank You for advice

[Payne]

For those of you who struggle with calibration, and it doesn't work, try to turn on both the yellow and blue channel, and make the calibration.

Now you will see a bar graph moving for quite some seconds, followed by "Success"

This will cure the DC offset problems

[Payne]

Regarding the 250ns problem: I don't know if anybody else experience that sinus, sawtooth, triangle, signals like that easily can be triggered, also in 10ns-250ns.

But if I try to trigger on a square wave BELOW 90kHz, then the trigger does not work from 10ns-250ns

As soon as the square wave frequency is higher than about 100kHz the trigger works fine

[beamertt]

Regarding the 250ns problem: I don't know if anybody else experience that sinus, sawtooth, triangle, signals like that easily can be triggered, also in 10ns-250ns.

But if I try to trigger on a square wave BELOW 90kHz, then the trigger does not work from 10ns-250ns

As soon as the square wave frequency is higher than about 100kHz the trigger works fine

My scope (still running on V164) does kind of trigger on 80kHz square wave in 10ns-250ns time base but there's a huge difference between Runmode High or Normal and whether I select only channel 1 or both channels:
Runmode High with only Channel 1 enabled looks horrible. I'm avoiding Runmode High as much as possible for now...
 

[Payne]

If you struggle with fully attaching or removing the probes from the BNC connectors, you can remove the black sticker, which peels off easily - then the probes attaches easily

[beamertt]

Yep, mine was way to tight too. I initially tought I would never be able to remove the BNC connector without breaking the unit...
So I just opened the casing and cut the BNC holes bigger so it fits properly.
For the people with a 3D printer, on thingyverse there is also someone who made a "leaner" probe cover with thinner bottom:
https://www.thingiverse.com/thing:7053840

[ME]

I haven't installed the new software yet but I was using the 703S yesterday and I noticed that no matter what I set on the display menu tab, even if I set it to off, the display switches off at what appears to be the same period of time, I don't want it to switch off at all! most annoying when I am working on the bench, just in the middle of a measurement and the damn thing goes off!

Did this get fixed as my 703 is on boot v1.0.16
app v1.6.4
Its doing the same and driving me nuts!.

[ME]

For all the bugs this meeter has, I am amazed how well it was calibrated at the factory.  I have a number of .1%, 10ppm resistors and it reads them nearly perfectly.  The one issue I have though, is you need to have it in the correct range when you use the "Rel" function.  I don't remember this being an issue with any other meters I have.  For instance, if I null the meter and then try to read a 1k resistor, it is out of range.  You need to select the correct range for the DUT and then hit "rel".

Jerry

If i remember my fluke 83 does the same!.

[Instagibz]

Does anyone have spare a ME4086A? Just let me know how much you want for IC+Shipping to germany

[zenon]

"Does anyone have spare a ME4086A? Just let me know how much you want for IC+Shipping to germany"

Keep this in mind:
https://www.eevblog.com/forum/testgear/zoyi-zotek-zt-703s-fire-hazard-while-charging/
AliExpress
https://www.aliexpress.com/item/1005009303293303.html
You can buy ICs from AliExpress, but I use an external charger because I don't trust the Chinese very much.

[tol]

Does anyone have spare a ME4086A? Just let me know how much you want for IC+Shipping to germany

I don't have it but I asked a few random Aliexpress sellers from China and they are willing to send it, the price is USD 1.23 for one. Not sure about shipping fees to Germany though. I did not order it as there is really no need for it until you replace the battery that was installed by Zotek. This battery has internal overcharging protection and it seems to work. If the original battery is already dead and you want to replace it with a standard battery without protection, then you need to replace the chip as well to prevent possible fire.

[SammysHP]

AliExpress
https://www.aliexpress.com/item/1005009303293303.html
You can buy ICs from AliExpress, but I use an external charger because I don't trust the Chinese very much.

Unfortunately this item is not available in Germany.

This is the only item that is found when searching for "ME4086A": https://aliexpress.com/item/1005010452531322.html

there is really no need for it until you replace the battery that was installed by Zotek. This battery has internal overcharging protection and it seems to work.

The battery that came with my device it is not rated for 4.35V according to its datasheet. The protection circuit is triggering repeatedly when charging restarts (that causes the blinking of the power button), keeping the voltage well above 4.20V.

[zenon]

"This is the only item that is found when searching..."

I think you can order it, from the link you gave.
Here is what a user who purchased this IC wrote, from the link I attached and referring to the same IC:
"Charging as expected now to 4.17v in my zoyi zotek zt-703s."

Happy holidays!

[Payne]

Some measurements for using the ZT-703s - if anybody can use

[Payne]

Another finding: If you use the internal generator for, let's say sinus wave, then you cannot go lower than 100usec/division - but if you Hold the signal, you can go down to 1usec and "inspect" the signal.

I use FW 1.4.2 which I find the best one

[ME]

Another finding: If you use the internal generator for, let's say sinus wave, then you cannot go lower than 100usec/division - but if you Hold the signal, you can go down to 1usec and "inspect" the signal.

I use FW 1.4.2 which I find the best one

Can you explain what you mean by "HOLD" the signal and tell us how you do it?.

[Payne]

Another finding: If you use the internal generator for, let's say sinus wave, then you cannot go lower than 100usec/division - but if you Hold the signal, you can go down to 1usec and "inspect" the signal.

I use FW 1.4.2 which I find the best one

Can you explain what you mean by "HOLD" the signal and tell us how you do it?.

Just press the "Hold/Save" button a short press....

[ME]

Can this thing output a sinewave from the sig genny at the same time in the scope xy mode?, it turns to squarewave as soon as the scope is turned on on mine !.

[Payne]

Can this thing output a sinewave from the sig genny at the same time in the scope xy mode?, it turns to squarewave as soon as the scope is turned on on mine !.

Mine can do it - fw 1.4.2

[Payne]

AliExpress
https://www.aliexpress.com/item/1005009303293303.html
You can buy ICs from AliExpress, but I use an external charger because I don't trust the Chinese very much.

Unfortunately this item is not available in Germany.

This is the only item that is found when searching for "ME4086A": https://aliexpress.com/item/1005010452531322.html

there is really no need for it until you replace the battery that was installed by Zotek. This battery has internal overcharging protection and it seems to work.

The battery that came with my device it is not rated for 4.35V according to its datasheet. The protection circuit is triggering repeatedly when charging restarts (that causes the blinking of the power button), keeping the voltage well above 4.20V.

If you want to avoid changing the charge protection IC, and you want to protect the battery, you can also just avoid charging the battery fully by keeping an eye on the charge current with a USB charge monitor, and stop the charging when the current starts dropping in the CV phase

[Skander]

Can this thing output a sinewave from the sig genny at the same time in the scope xy mode?, it turns to squarewave as soon as the scope is turned on on mine !.

Mine can do it - fw 1.4.2

You must use the limited sig. gen. menu on the oscilloscope mode "Output setting". Those changes can apply and persist while using the oscilloscope.
If you go though the "More apps" dedicated (and more capable) signal gen option, you can only use that while the app is open. The moment you leave, it will reset to the settings in the limited menu.

Does not depend on fw version.

[tol]

If you want to avoid changing the charge protection IC, and you want to protect the battery, you can also just avoid charging the battery fully by keeping an eye on the charge current with a USB charge monitor, and stop the charging when the current starts dropping in the CV phase

I can tell you that it will not work. We usually connect the usb cable and go to do some other things, and forget about charging, so it will charge to full in 99% of all charges. The only thing why I don't replace the charge controller is that this device is several years on the market and nobody reported any fire issue or battery degradation yet, so the internal battery protection works fine. It's true that the charging voltage is too high for this type of the li-ion battery and the led blinks at the end, but I don't see any issues after 1 year of use, the battery still works as it should, so I think the replacement of the charging controller is not required unless someone replaces the original battery with some other one, that may not manage the higher charging voltage the same way as the original one does. It's more about the feeling to be on the safe side, I think. Maybe I will also replace the charging controller some day, but not sooner than I want to replace the original battery Or maybe I will replace the whole device with something better and throw it away until the day when the original battery becomes completely unusable