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

[ksxx]

The measurement values in Scope mode seem to have more problems than I thought before when in DC input mode(FW1.32). I measured the switching on signal of my PSU at 12V setpoint. I set the scope to 100ms/div and 5V/div. The signal on the screen clearly shows the 12V amplitude of the voltage ramp. The vpp,max,min values are completely off and do depend on where I set the vertical offset.
Zoyi please fix this. I cannot imagine that this is hard to do.

looks like this issue is fixed in fw 1.35. The min/max measurements still give funny results in roll mode and stopped. Btw, the trigger level value shown at the top is nonsense. Note , the trigger vert position on the Zoyi is always related to the screen coordinates. When you switch the vert sensitivity , the trigger arrow stays at the same position. A bit unusual for me, but for this small unit maybe not a bad choice. 

[ksxx]

I did some tests with the Zoyi and some other meters I have access to. The AD780 was trimmed to give a 2.5000V output on the (old) HP desktop meter. The film capacitors were measured with an Agilent 4294A impedance analyser at 10KHz. The table shows that my 703S gives the results closest to the ones by the more advanced equipment. Yet most of the meters tested do well enough for most situations. Even the 10$ T7 component tester gives great results!

[lazalem]

Good Day!

Just want to know if ZT-703S is a good multimeter+oscilloscope for a hobbyist like me.  I am coming from a DSO150.  Which is a better buy among these:

Zoyi ZT-703S ~ 37.80USD (New)
Owon HDS242S ~ 74.16USD (New)
Owon HDS2202S ~ 78.07USD (Used)

At double the price, does the owon variants have better features, accuracy, reliability?


Thanks!

[Vapor8]

I did some tests with the Zoyi and some other meters I have access to. The AD780 was trimmed to give a 2.5000V output on the (old) HP desktop meter. The film capacitors were measured with an Agilent 4294A impedance analyser at 10KHz. The table shows that my 703S gives the results closest to the ones by the more advanced equipment. Yet most of the meters tested do well enough for most situations. Even the 10$ T7 component tester gives great results!

Would you mind sharing what version firmware the Zoyi 703S used in your testing has? Thanks!

[ksxx]

Would you mind sharing what version firmware the Zoyi 703S used in your testing has? Thanks!

fw was 1.32. I now tried 1.35 and there is no change in the results (as I would assume).

[lchao]

Good Day!

Just want to know if ZT-703S is a good multimeter+oscilloscope for a hobbyist like me.  I am coming from a DSO150.  Which is a better buy among these:

Zoyi ZT-703S ~ 37.80USD (New)
Owon HDS242S ~ 74.16USD (New)
Owon HDS2202S ~ 78.07USD (Used)

At double the price, does the owon variants have better features, accuracy, reliability?


Thanks!

Where did you find these prices? I can find just these lowest prices:
Zoyi 703s shipped to the Philippines is USD 75 on Aliexpress,
Owon HDS242S is USD 144 on Banggood at the moment
Be careful, because sometimes the price os other models are shown if you search for these products (e.g. Zoyi 702 and Owon HDS242 - which doesn't have signal generator)

The 2 products are close to each other in specs, but Owon is double the price. I'm not an electornics expert at all, but based on what I've read so far I found the Owon HDS242S far better than the Zoyi 703s.

Pros for Owon HDS242S compared to Zoyi 703s (for me):
- It seems it has the same hardare as the 70 MHz model, therefore the signal amplitude doesn't shrink even when measuring above 30MHz
- Usable signal generator (Zoyi 703s is very noisy -> low quality, signal output is not BNC)
- Works as described, it meets the specifications
- Has more probe settings e.g. x1000, x10000  (Zoyi has x100 starting since a recent firmware update)
- 4400 mAh battery capacity - 2x 18650 battery (vs. 3400 mAh, 1x 18650 battery in Zoyi)
- Horizontal scale: 5ns/div-1000s/div (Zoyi has 10ns/div-20s/div)
- Stable and accurate software (Zoyi has a lot of inaccuracy issues in the measurements)

Cons for Owon HDS242S compared to Zoyi 703s:
- Has only 8K memory (Zoyi has 128K)
- Multimeter part has "just" 20 000 counts (Zoyi has 25 000)
- It seems firmware is not being updated (Zoyi is continuously gettig FW updates - unfortunately it doesn't mean that all known issues are fixed)
- Somewhat lower bandwidth based on specs: 40 MHz (Zoyi _claims_ 50 MHz, but while you can measure in Owon's full specified bandwidth, with Zoyi's it's not the case)
- Only sold with 1 probe (Zoyi is sold with 2 probes as an option)

All in all I found the HDS far more superior than the Zoyi, but it also comes with an almost 2x price tag.

DISCLAIMER: I have very limited knowledge in electronics. This is solely my opinion and understanding based on the information from manufacturers or elsewhere I found on the Internet. I don't own any of these products.

[jeremybh1]

Just as I was warming to this device it's let me down in testing in-circuit AC readings.
It shows a voltage then goes to 0, setting the range manually does nothing.
Use case: Macintosh Plus vintage computer power supply.  Visual map of what expected in-circuit voltages should be in both AC and DC.
Uni-T 61 shows expected 20VAC on cathode and Zoyi 703 just couldn't lock on. 
Was able to repeat this failure of flashing a reading then going to 0VAC on other test points too.

So I can't quite use this as a multimeter

[csuhi17]

Owon is more imprecise, but more reliable in my opinion.

Owon also has hardware errors, the HDS2202 series drains the battery quickly, consumes 1.3A current.
There are times when the message Low battery appears on the display, but the device continues to operate for an hour or so.
There is sometimes a slight DC offset, perhaps due to heating.


But it is true that the function generator is very good.
Its structure creates a professional feeling, it is quite tough.
It also has some good sides, for example 1Gs/s even with two channels.
But for the rest, sampling is halved! From HDS242 to HDS2102

For 78 USD, I think it's worth it, even if you look at the small memory 8k. This is just my personal opinion.
I have not yet seen a video in which they tested whether the Zoyi use its 128k memory in all time bases.
Fnirsi has already surprised me... In a bad way...

To be honest, I have not yet seen a study in which they discuss the minimum amount of memory required for different measurements.

[lchao]

Firmware version: V138.

Modifications:
- multimeter mode memory function, which will record the last measurement gear after turning on and off or switching modes,
- optimizing the AUTO function,
- repairing the closed channels that will be opened during automatic measurement,
- repairing the difference in true effective values
- inaccurate position measurement problem

[Evi]

I noticed that Fcnt works correctly only with squarewave signals. FW latest 138.

[petters]

I have updated the firmware using v1.2.8 from the szzotek.com website and it works well on my unit (boot v1.0.15) although I still cannot tell what is changed in this version

If someone from Zotek is reading this: PLEASE put in an option to mute the beeps and bring back the temperature reading!!! We will supply our own thermocouples!

I really want this multimeter as a nice little all-in-one but the lack of thermocouple/temperature measurement is a big turnoff. That being said, the https://zotektools.com/products/zoyi-zt-703s/ website shows
"Temperature" under features and the image even has the probe icon printed above the jack unlike the 703S listings on Amazon and Aliexpress. Maybe we need to wait for the market to sell off the existing ones before we see the most recent version for sale?

[Astur_TorQue]

zoyi said they had problems to implement both temperature sensor and two channel system at the same time

[mf2105]

*** newbie here, sorry for any inconvenience ***
Is there any reason NOT to install firmware 1.38?
Seems the youtuber tim1tim2 is a insider of the manufacturer or at least related to https://thedmm.com/ and didn't mention it at its channel at all!?
https://www.youtube.com/@tim1tim2
Last video is from may-01

[black6host]

*** newbie here, sorry for any inconvenience ***
Is there any reason NOT to install firmware 1.38?
Seems the youtuber tim1tim2 is a insider of the manufacturer or at least related to ...

I've installed it and found no troubles.  I like the fact that it stays in the last mode you left it in.  I did have one incident where I had left it overnight and I swore it had 3 bars of battery life.  Went to turn it on the next day and it was dead as a door nail.  Charged it back up and haven't had a problem sense.  I'm not saying it's related to firmware 1.38 at all.  Only that that had never happened before so who knows...  I mention it in case anyone else has ever seen similar.

[sergkz]

hi all! became the owner of 703s
Firmware 1.38 seems to have a problem with AutoRange at high frequencies
4mHz - ok
24mHz - not ok
took measurements from quartz oscillators on the device board
at a frequency of 24 MHz it begins to detect normally if you rearrange the x10 divider on the probe itself
on x1 does not see generation
---------------
Sorry for my English - I'm writing through an online translator

[m72]

24mHz - not ok
at a frequency of 24 MHz it begins to detect normally if you rearrange the x10 divider on the probe itself

Hello!

The capacity of the probes in X1 mode is ten times greater than the capacity of the probes in X10 mode. Such a large capacitance greatly affects the operation of small circuits such as a quartz resonator.
Moreover. In X1 mode, the recommended frequency of the signals under study should be in the range of 5-10 MHz, then you should switch to X10 mode.

With best regards.

[EU1]

High resolution images here: https://imgur.com/a/c2Oi1iY

Thanks for the excellent photos!

Does it charge the battery to 4.34V? The charger IC is an ME4059D, which has a fixed charge voltage of 4.34V.

[m72]

Does it charge the battery to 4.34V? The charger IC is an ME4059D, which has a fixed charge voltage of 4.34V.

The battery charges up to 4.25 volts. This may be the result of the built-in battery protection and therefore the charging LED blinks right before it is completed.

[PCB.Wiz]

Firmware version: V138.

Modifications:
- multimeter mode memory function, which will record the last measurement gear after turning on and off or switching modes,
- optimizing the AUTO function,
- repairing the closed channels that will be opened during automatic measurement,
- repairing the difference in true effective values
- inaccurate position measurement problem

I have the 703S, and the features/money is quite impressive.
I would like to measure Pulse Width negative / Pulse width positive on single shot pulses. (monostable calibration checks)

Does anyone know if a firmware update plans to add Pulse Width negative / Pulse width positive ? (on single shot pulses ? )
138 seems to be the latest ?

[canvas]

Just pick up a zt-703s with FW 1.3.5. I found a problem. I measured my battery (8.22V) with reversed polarity, the MIN will max out at -1V. Updated to FW 1.3.8, it's better, I got -8V for MIN, but the actual reading should be -8.22V.  On the other hand, MAX reading was fine and accurate. Is there anyone having this problem too?

[koks1960]

Yes, there is such a problem too. Firmware 1.3.8, you will have to observe the polarity of the probes when measuring.

[bobuhito]

I just bought a new ZT-703s and, for the record, the board is marked "v2.2" (which is newer than anything I've seen online) and "202403 12", as shown in the image below (they even missed removal of some chip markings, revealing the clues "D" and "R").  The battery is still tightly-packed, but I'm probably not going to touch the spring.

It shipped with firmware 1.3.2, and I quickly updated it to the latest 1.3.8.  I'm mainly using it to read voltages and check slow flicker noise (over the course of minutes) with the serial UART 3Hz-logging feature mentioned earlier in this thread.

I *believe* voltage readings are a little out of spec on this unit, reading 10.015V on what was once a 10.002V reference (but is now uncalibrated).  I did not get a stamped QC card, which some online videos show to be included, so I wonder if this unit was even calibrated.  In case anyone is in the Minneapolis area in USA with a precise voltage reference/meter and wants to look at this device (of course, it's really just a favor to me!), please contact me.

[xKertx]

I received my ZT-703S yesterday.
I also got the "newer" version.
PCB version: v2.2
Boot version: V1.0.16
APP: V1.3.2 > updated to V1.3.8

And in my unit the marking on the chip is also partially visible (D and R visible).

One thing that is strange for me is that the metal can that covers the scope input is left partially open on the both sides. Is that so on the older models also?
Would it make any difference if i solder a copper tape over the openings, so it would be completely covered?

[GnatGoSplat]

That made me curious to open mine that I ordered in March and received early April.  Also v2.2, but date is 20240222.  No visible D and R.

[bobuhito]

@xKertx
I didn't notice this before, but now see that my can is "partially open" too.
I imagine they did this to let heat out, so I would not cover it up with copper tape.