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

[Edmiri]

I have tried repositioning the probe leads and had no diference. I also tried reel mode and same results.
Strange why it didnt read at all when connected directly to the input terminals.
Also why it needs some minutes of usage before the capacitance value raise.  This is for both stock probe and Bside twezers. After it warmed up i read even 1pf capacitor using bside tweezers.

[indman]

We should expect to have some measured C of the probe set, but certainly the reading will depend on how the lead wires cross over each other and how close the ends are to each other. It is perhaps possible that the 16pf set could read 45pf if the leads were arranged differently?

No,there won't be that much change in capacitance. Of course, it will vary in some limits from the position of wires in space, but such a capacitance of 45-50pF, which has tweezers, is unlikely to reach. I could be wrong of course, I just wanted to explain this effect with different probes, which observes Edmiri.

I have tried repositioning the probe leads and had no diference. I also tried reel mode and same results.
Strange why it didnt read at all when connected directly to the input terminals.

As I see from your last message, you still did not quite understand the meaning of what I was trying to show in my photos and in the message above. Perhaps because of my bad English? Sorry! Maybe someone else who understood what I wanted to say will explain it to you more clearly.

[Edmiri]

You we're very clear.
What i don't understand is why when i directly connect the capacitor to the multimeter without any probe, it doesn't show any value. Larger than 33pf ca0acitors show value, so this means the connection is ok.

[indman]

What i don't understand is why when i directly connect the capacitor to the multimeter without any probe, it doesn't show any value. Larger than 33pf ca0acitors show value, so this means the connection is ok.

Once again, I'll try to explain to you why this is the case. You see the numbers 00.000nF on the display of the ZT-703S with no capacitance connected. In reality, this is not the case. Imagine that now your device displays a conditionally negative value (-00.033nF). When you connect a 33pF capacitance directly to the input pins, this conditionally negative value is compensated and you can see that the display shows no change, i.e. it shows 00.000nF. If you connect another capacitance directly to the input jacks, e.g. 100pF, you should see a result of about 00.067nF on the display, i.e. 100pF-33pF=67pF.

[m72]

My observations.
The multimeter is a separate part of the circuit. The most common and widespread multimeter made on DTM0660/DTM1106. Therefore, any answers to the topic “how it works” and “what to do with it” can be found in topics about this chipset. There will be nothing new here. All the nuances, all the limitations stem from the capabilities of the DTM0660.
a) It can be calibrated at any time by recording what you need in I2C EEPROM. I remade the current shunt, calibrated it by writing down the settings at address 0x2A and got an “ideal meter for 4-20 mA”. In Russian it's "as easy as to send two bytes."
b) When switching to a multimeter, its mode will always be voltage measurement because no one bothers with maintaining the operating mode. Yes, in fact, this is unlikely to work out in this circuit design.

[indman]

The multimeter is a separate part of the circuit. The most common and widespread multimeter made on DTM0660/DTM1106. Therefore, any answers to the topic “how it works” and “what to do with it” can be found in topics about this chipset. There will be nothing new here. All the nuances, all the limitations stem from the capabilities of the DTM0660.

The ZT-702S multimeter uses DM1109EN and EEPROM 24C02 chip. In the ZT-703S, the multimeter chip is still unknown since the markings have been erased and EEPROM 24C02. There are many similarities with the DTM0660, but there are also differences.

a) It can be calibrated at any time by recording what you need in I2C EEPROM. I remade the current shunt, calibrated it by writing down the settings at address 0x2A and got an “ideal meter for 4-20 mA”. In Russian it's "as easy as to send two bytes."

Not all calibration constants and configurations are stored in the I2C EEPROM, so for each device model the contents of the EEPROM will differ significantly. There are many things that are already pre-recorded at the factory into the main DM chip and their value cannot be changed or a special calibration procedure is required, which is known to the manufacturer!

[MarkusWandel]

This is odd.  The Zotek website offers v1.27, and that's what people seem to be generally talking about.  But the one I just got shows firmware 1.30.

Interesting bugs found so far:  While showing it to a friend, first the trigger position indicator disappeared.  Only the tiny green right arrow at the top right showed, but no amount of scrolling left and right brought the trigger position into view, and in fact, scroling was infinite since it kept wrapping around.

Shortly after that, the trigger mode button stopped working.  It was just stuck in "Auto", no way to go to single shot any more.  Toggling the unit off and on, and toggling between scope and multimeter mode, changed nothing.  Resetting the scope to defaults fixed it.

Also, shouldn't there be a way to change the scale/position settings for channel 2?  Selecting channel 2 in the menu affects nothing; the directional buttons still change channel 1.  The only way I've found is to disable channel 1 temporarily; then they access channel 2.

One hopes for active bug fix updates.  But again, why do I have newer firmware than what is downloadable?

Main dislike other than the issues above, is that the buttons need a pretty heavy press.

[ksxx]

Also, shouldn't there be a way to change the scale/position settings for channel 2?  Selecting channel 2 in the menu affects nothing; the directional buttons still change channel 1.  The only way I've found is to disable channel 1 temporarily; then they access channel 2.

This sounds annoying... Will receive mine in the next few days. I will most likely use only 1 channel 95% of the time. What can we expect for around 80€ only? Lets see if we get more FW updates or if Zoyi rather releases a new scopemeter model.

[MarkusWandel]

Another question, is everybody's ZT703s as noisy as this one?  Probe clipped to the calibrator output/ground lug, default square wave output, haven't messed with the calibration screws yet.

About 2-3 pixels of noise regardless of the vertical scale.  Even with the probe grounded, at some vertical scales about 2 pixels of noise are present as in the last screenshot; at others the line is flat.  Par for the course at this price level?

[Hoggy]

Another question, is everybody's ZT703s as noisy as this one?  Probe clipped to the calibrator output/ground lug, default square wave output, haven't messed with the calibration screws yet.

About 2-3 pixels of noise regardless of the vertical scale.  Even with the probe grounded, at some vertical scales about 2 pixels of noise are present as in the last screenshot; at others the line is flat.  Par for the course at this price level?

I've noticed the same thing - and was wondering if it was just me...

My 3 cheapie ZeeWeii scopes don't show this much noise.

[Mortymore]

Glad that they don't show perfect lines, as they seem to show perfect zeros on multimeter, to make some users happy 

[indman]

Glad that they don't show perfect lines, as they seem to show perfect zeros on multimeter, to make some users happy 

Bingo,you think right! Beware if you see a straight, nice and noiseless sweep line on digital oscilloscopes, as well as absolute zeros on the display when measuring capacitance!

[MarkusWandel]

Next one:  I haven't found a way to display absolute voltages for the horizontal cursors; it only displays a delta.

As long as the voltage graticule is accurate (with the channel zero point arrow lined up visually) one can just place one cursor on, say, 0V and then read the absolute voltage for the other off the delta.  But  have I missed something?

[MarkusWandel]

Beware if you see straight lines on cheap oscilloscope that is.  My previous experience with a digital scope, when I was still doing that sort of analog lab work, 30 years ago, was with a HP 54100.  And that one really did give clean lines - at higher pixel resolution too - for DC values.

[MarkusWandel]

Watched the video above.  Admittedly all the work with the old expensive early generation digital 'scope was in single-shot mode.  And I don't have any screenshots left (hardcopy in those days - you hooked up a printer via HPIB) to really confirm that my memory is accurate.

[Fungus]

Next one:  I haven't found a way to display absolute voltages for the horizontal cursors; it only displays a delta.

As long as the voltage graticule is accurate (with the channel zero point arrow lined up visually) one can just place one cursor on, say, 0V and then read the absolute voltage for the other off the delta.  But  have I missed something?

STOP it then use the trigger level as a "cursor".

[MarkusWandel]

Is this more "don't expect too much from a cheap scope" stuff?  I clipped both the probes (P2060) to the calibrator lug - and the ground clips to the ground lug - to finally adjust the compensation screws.  Nice and rectangular, but... different amplitude?  I figured OK, cheap probes, don't exactly do 10:1 attenuation (both were switched to 10X).  But swapping the BNC connections didn't change anything.  Channel 2 still shows the same, lesser amplitude.

[wasedadoc]

Is this more "don't expect too much from a cheap scope" stuff?  I clipped both the probes (P2060) to the calibrator lug - and the ground clips to the ground lug - to finally adjust the compensation screws.  Nice and rectangular, but... different amplitude?  I figured OK, cheap probes, don't exactly do 10:1 attenuation (both were switched to 10X).  But swapping the BNC connections didn't change anything.  Channel 2 still shows the same, lesser amplitude.

If you have not done so already, try doing the calibration.

[kloetpatra]

It looks like new stock is sold with 1.3.0 Firmware. However it is still nowhere to be found online.

[Harrow]

My ZT-703S arrived today, purchased from AliExpress. I was surprised it wouldn't turn on since the batteries are usually delivered with 50% charge. I opened it up and found that I have no battery inside!!!

I'm wondering if it's worth the effort of sending it back, or probably I'll just buy a battery and put it in myself. Does it matter if I install an ICR or IMR 18650? Are they interchangeable? Which should I be using in this?

[Razvan_N]

They are both compatible, but I would use ICR. IMR is for high drain applications, it would be overkill for a scope.

[indman]

I'm wondering if it's worth the effort of sending it back, or probably I'll just buy a battery and put it in myself. Does it matter if I install an ICR or IMR 18650? Are they interchangeable? Which should I be using in this?

What do you need to buy a battery for now? You can check if the device works by simply connecting an external 4.0V voltage to it, e.g. from a power supply unit.
If the device works in all modes, simply negotiate with the seller for compensation for the missing battery. If the device is not working, you should return it to the seller.

[Harrow]

What do you need to buy a battery for now? You can check if the device works by simply connecting an external 4.0V voltage to it, e.g. from a power supply unit.
If the device works in all modes, simply negotiate with the seller for compensation for the missing battery. If the device is not working, you should return it to the seller.

Thanks. This is the first time I've used AliExpress. I just found the 'Message Center' and contacted the seller. I had connected power to it and it does work, so hopefully they can simply send me a battery.

Otherwise, I'm quite happy with the unit and how it works. Having grown up using hefty Tektronix CROs in the 80s, I'm still boggle-minded that I can have this in my hand for under $100.

[Maksnav]

I just wanted to post a PSA, most probably know this already but when buying anything of value from AliExpress please video record the opening of your package in one continuous shot all in frame.

I purchased the ZT-703 2x now from AliExpress the first one was returned to the seller because the package weight didnt match the discription during shipping and never made it out of china. The second one was flat out scammed and the seller sent me some gel pads that look like small shoe inserts or something. It came in a large order with several items. The recording i made was corrupt (not sure what happened) Luckily AliExpress refunded my purchase without it. Ended up buying a ADS1013D for 50$ off ebay for use in the mean time. Again just wanted to share my cautionary tale.

[ksxx]

Just got my 703S. It took me some time to realize that the function generator available via the 'More Apps' menu does not work together with the scope functionality at all. Either use the scope or the enhanced function generator! The low frequency generator accessible via the 'Output' option on the other hand is always available. However it seems that setting some of the other waveforms (triangle etc) then imposes a 100us minimal timebase setting.

fw is 1.29