Hello Kerry, when you need to measure signals of more than 30 Mhz it is necessary to change from the menu to high speed mode, this way you go from 200 MSa/s to 280 MSa/s, doing this the wave remains stable up to 46 Mhz in the 2 oscilloscopes I bought. Greetings.
Zotek updates the firmware. There is a pointer on Zotek’s product web page for both the 702S and 703S to Google Drive pages with the current firmware. There were updates for both models newer than as shipped. The 702S update fixes the pose up in last mode used issue.
@@KerryWongBlog Thanks for the reply. There were noticeable improvements to the 702S. The 703S changes were less obvious. The 702S I have is branded Aneng, but it had no issues running the firmware downloaded update from the Zotek site.
The offset issue is that the 703S tries to center the waveform assuming that you want to display two non overlapping channels simultaneously - it does that even if only only one channel is enabled.
Professor Wong, question. You mentioned the meter graphic does not keep up with the digital count. Will it keep up with aligning a circuit such as when aligning for finding a voltage peak while slowly adjusting a slug in an RF or IF can or an audio stage? Some lag time is acceptable since these adjustments are done slowly; your thoughts Sir. I really enjoy and value your lectures as part of my ever ongoing opportunities to expand my knowledge. A 4-year E.E degree, 1970's, basically means one is capable of and must learn more; it never ends !!
The 703S I received came with an installed 3600 mAH 18650 cell with internal overcharge protection. There seems to be an interaction with the main board charge controller and the cell OVP which makes the power button red light flicker annoyingly near full charge. I installed another cell without the internal OVP and there was no flickering.
The 1.3.9 firmware is a big improvement to the oscilloscope mode. This release fixes the trigger instability which made it difficult to lock onto non sinusoidal waveforms greater than a few MHz. Switching between normal and fast refresh is now smoother and faster.
@@KerryWongBlog I have tried two of these and the temperature scale was way off, 91 C for steam from a kettle and 95 C on the second unit. Not in keeping with the rest of the performance.
Thanks for the video! Do you happen to know of a portable scope or meter that can log a graph from an input from a current clamp as a simple line of RMS that is easy to read by someone not accustomed to reading sine waved?
You want a dmm (set to measure AC volts) with either a logging function, or a serial (rs232, usb, Bluetooth or infrared) output that you can capture using a laptop or phone. Then either plot the numbers in excel or get the dmm to plot its logged data on screen. An example is the owon b35t+ which has Bluetooth. (And also apparently logs, but we're not using that) I have not used one but I expect this would do it. I'd expect to use Putty to capture the text output from the Bluetooth com port. Again, details need checking before you assume this is going to work - for all I know it might only talk to a dodgy phone app.
Thank you! I saw discontinued southwire 15190t with voltage logging and a phone app, which inspired the idea, but the app is no longer supported. Also not sure if the response would be fast enough to catch inrush currents . Il look into your suggestions!
After watching a couple of these cheap scope meters, I'd rather spend a bit more so I'm not messing around as much. Would you recommend an Owon model to me or something similar?
is the BNC ground connected to COM ground? thats a major safety issue as the bnc's are exposed metal not the plastic type ones. i like the old ths720 from tektronix they are slow have a horrible display and almost no memory as they are from the 90s but all their channels, dmm and ch1 ch2 are isolated from eachother and have plastic bnc sockets to not get shocked capacitively when measuring mains with the DMM a nice feature id like to see on those new chineses pocket scopes aswell
Hi, great review, as usual. But may be you missed a power saving option that can trigger the default sampling at 200 Msa (33 Mhz) to the 280 Msa(50 Mhz). It's page 19 of the user manual. Thanks for your awesome videos.
Kerry. Another gotcha that had me scratching my head for ages. There is a note in the manual that if the Func Gen is running non-square wave, the horizontal timebase is limited to 100us/div. So to get faster horizontal timebase you have to have Func Gen set to square wave. See Note on bottom of page 20 of manual. Cheers. Great videos Kerry.
I am missing a BNC connector for the Function Generator output. Osciloscope recording, firmware soft updating, laptop signal exporting, CAT rating for BNC connection or screenshot processing were not assessed. It would be a great chance to compare this OMM with the similar FNIRSI 2 chanel one, despite the last goes only up to 10 MHz (but has an less noisier BNC function generator output).
The specified peak voltage is 300V in oscilloscope mode, so you could with 110V mains voltage. But for 220V, the peak would be just over the specified maximum (310V).
Kerry, with the faster sampling rate engaged, can the scope BW be verified at 50Mhz? Also, agreed with the bargraph in the multi-meter mode. Doesn't add much. I wish the manufacturer would change that, and possibly just put up a graphic reminding where the probe leads should be plugged in. Great video review BTW! KUDOS.
@@KerryWongBlog Thanks. I saw that video and you indicated 46Mhz was the actual bandwidth.That's 8% off a primary performance spec on the scope. I was interested to know where one might send feedback and had you done so.
4 месяца назад
There's a fast and a normal acquire setting. For 50 you change it to fast
Also there's a new firmware update. Since 1.3 the only changes are: "improved some apps", correction of indication, better rms measurement and save multimeter ranges. Nothing significant. But it's worth doing the update, for me it seems like there's less noise on both channels, but sampling got messed up, at high frequencies sometimes artifacts appear on the wave forms.
What you attached it’s not a termination Z but an attenuator. For termination you need to install a Tee. This is an honest oscilloscope. The performance / specs vs cost ratio is great. Again, great value for your money
It could be a feed through termination. I have several Tektronix feed through terminators - they’re better than tees because there is not even a short stub to create reflections - though at the maximum frequency usable on the 703S, a tee would be fine. I found about the same frequency response as Kerry on my 703S with the most current firmware downloaded from Zotek’s Google drive page point to from the Zotek product description page on their web site.
The REL function is on the red power button. Momentary press for REL. Press and hold to power off.
Hello Kerry, when you need to measure signals of more than 30 Mhz it is necessary to change from the menu to high speed mode, this way you go from 200 MSa/s to 280 MSa/s, doing this the wave remains stable up to 46 Mhz in the 2 oscilloscopes I bought. Greetings.
Maybe you also have to set the scope & probe to x10 (like on most other scopes) Just a info
Zotek updates the firmware. There is a pointer on Zotek’s product web page for both the 702S and 703S to Google Drive pages with the current firmware. There were updates for both models newer than as shipped. The 702S update fixes the pose up in last mode used issue.
I will be updating the firmware for my 702S and 703S soon. Will provide an update.
@@KerryWongBlog Thanks for the reply. There were noticeable improvements to the 702S. The 703S changes were less obvious. The 702S I have is branded Aneng, but it had no issues running the firmware downloaded update from the Zotek site.
If you update the zt702s it will remember your last settings on power up.
The offset issue is that the 703S tries to center the waveform assuming that you want to display two non overlapping channels simultaneously - it does that even if only only one channel is enabled.
58 level F/W on the 702 permits it to boot up in last mode. I did have to repair the 702's F/W folder to enable it's update. Nice review.
Thanks for letting me know!
The 703S manual is very well written. It’s worth reading BEFORE doing the full product review (in my opinion).
😂that will be the day that they read before spilling misinformation
Thanks for the review. Shame that the function generator does not have a BNC connection.
Professor Wong, question. You mentioned the meter graphic does not keep up with the digital count. Will it keep up with aligning a circuit such as when aligning for finding a voltage peak while slowly adjusting a slug in an RF or IF can or an audio stage? Some lag time is acceptable since these adjustments are done slowly; your thoughts Sir.
I really enjoy and value your lectures as part of my ever ongoing opportunities to expand my knowledge. A 4-year E.E degree, 1970's, basically means one is capable of and must learn more; it never ends !!
@wa4aos, Are you referring to the oscilloscope or the DMM? In general though, if the voltage is slow varying then these meters will work fine.
The 703S I received came with an installed 3600 mAH 18650 cell with internal overcharge protection. There seems to be an interaction with the main board charge controller and the cell OVP which makes the power button red light flicker annoyingly near full charge. I installed another cell without the internal OVP and there was no flickering.
I just noticed the same flickering as well.
@@KerryWongBlog Thank you for confirming the behavior of the charge LED.
Firmware v139 is out
The 1.3.9 firmware is a big improvement to the oscilloscope mode. This release fixes the trigger instability which made it difficult to lock onto non sinusoidal waveforms greater than a few MHz. Switching between normal and fast refresh is now smoother and faster.
need help i just put my single probe on high voltage side without using the negative clip.. is there any fuse or something that i can fit it?
I've bought 702 single channel and they released this - much better one :(
Thanks. Did you ever find out the reason for this newer model lacking temp measurment?
My guess would be that the DMM chip they chose does not support temperature measurement.
@@KerryWongBlog I have tried two of these and the temperature scale was way off, 91 C for steam from a kettle and 95 C on the second unit. Not in keeping with the rest of the performance.
Thanks for the video!
Do you happen to know of a portable scope or meter that can log a graph from an input from a current clamp as a simple line of RMS that is easy to read by someone not accustomed to reading sine waved?
You want a dmm (set to measure AC volts) with either a logging function, or a serial (rs232, usb, Bluetooth or infrared) output that you can capture using a laptop or phone. Then either plot the numbers in excel or get the dmm to plot its logged data on screen. An example is the owon b35t+ which has Bluetooth. (And also apparently logs, but we're not using that)
I have not used one but I expect this would do it. I'd expect to use Putty to capture the text output from the Bluetooth com port. Again, details need checking before you assume this is going to work - for all I know it might only talk to a dodgy phone app.
Thank you!
I saw discontinued southwire 15190t with voltage logging and a phone app, which inspired the idea, but the app is no longer supported. Also not sure if the response would be fast enough to catch inrush currents . Il look into your suggestions!
@23:50 I think REL and Power Button are the same.
Oh, thanks for pointing that out. I didn't notice that. What an odd choice.
@@KerryWongBlogthey just released the 1.3.8 firmware. Might want to check this out and upload a follow up video if it fixed any issues. Thanks!
@@lazal3m Thanks for the heads-up! I will give it a try and provide an update.
Fair. I have had one for about 6 years. Only thing is I had to replace power supply cooling fan. $10.00 included tax and shipping. Not bad.
The "strange" channel numbering is probably because the designer looked at the inputs as in a regular scope front and you are looking from the back.
After watching a couple of these cheap scope meters, I'd rather spend a bit more so I'm not messing around as much. Would you recommend an Owon model to me or something similar?
is the BNC ground connected to COM ground? thats a major safety issue as the bnc's are exposed metal not the plastic type ones.
i like the old ths720 from tektronix they are slow have a horrible display and almost no memory as they are from the 90s but all their channels, dmm and ch1 ch2 are isolated from eachother and have plastic bnc sockets to not get shocked capacitively when measuring mains with the DMM
a nice feature id like to see on those new chineses pocket scopes aswell
No, the BNC ground and the DMM ground are isolated.
Hi, great review, as usual. But may be you missed a power saving option that can trigger the default sampling at 200 Msa (33 Mhz) to the 280 Msa(50 Mhz). It's page 19 of the user manual.
Thanks for your awesome videos.
Why does the pouch have a carry strap inside?!?
Microcontroller in question is GigaDevice GD32F4XX. Last two numbers are unreadable in my unit.
It's a Chinesium STM32 knock-off.
To measure 50MHz signal you have to select high speed mode (280Ms/s) instead of normal speed mode (200Ms/s).
Thanks for pointing out the high speed mode. I will try it out and will provide an update.
Kerry. Another gotcha that had me scratching my head for ages. There is a note in the manual that if the Func Gen is running non-square wave, the horizontal timebase is limited to 100us/div. So to get faster horizontal timebase you have to have Func Gen set to square wave. See Note on bottom of page 20 of manual. Cheers. Great videos Kerry.
@@joshuawhite2593 Thanks for the info!
Not impressed. It doesn't withstand the quality of my OWON HDS200. But it sure costs half.
Thanks for the detailed review/demonstration. It demonstrates the value of the unit.
I am missing a BNC connector for the Function Generator output.
Osciloscope recording, firmware soft updating, laptop signal exporting, CAT rating for BNC connection or screenshot processing were not assessed.
It would be a great chance to compare this OMM with the similar FNIRSI 2 chanel one, despite the last goes only up to 10 MHz (but has an less noisier BNC function generator output).
Hi was wondering if this would pick up signals in a automotive situations ie testing signals coming from senors. Thanks
Can it be used to measure smpsu primary circuits? Fraser
Question Kerry? Your thoughts on the Hantek DSO 5101p model Oscilloscope?
I don't have one so I can't comment on it.
Could you measure house voltage with this? Thinking about seeing the dirty electricity
The specified peak voltage is 300V in oscilloscope mode, so you could with 110V mains voltage. But for 220V, the peak would be just over the specified maximum (310V).
Kerry, with the faster sampling rate engaged, can the scope BW be verified at 50Mhz? Also, agreed with the bargraph in the multi-meter mode. Doesn't add much. I wish the manufacturer would change that, and possibly just put up a graphic reminding where the probe leads should be plugged in. Great video review BTW! KUDOS.
Yes. With the faster sampling rate, the bandwidth was just shy of 50 MHz. I did a followup video on this: ruclips.net/video/msZOJCR--Dg/видео.html
@@KerryWongBlog Thanks. I saw that video and you indicated 46Mhz was the actual bandwidth.That's 8% off a primary performance spec on the scope. I was interested to know where one might send feedback and had you done so.
There's a fast and a normal acquire setting. For 50 you change it to fast
Thanks. Will try and provide an update.
Also there's a new firmware update. Since 1.3 the only changes are: "improved some apps", correction of indication, better rms measurement and save multimeter ranges. Nothing significant. But it's worth doing the update, for me it seems like there's less noise on both channels, but sampling got messed up, at high frequencies sometimes artifacts appear on the wave forms.
W wersji 1.3 dochodzi też mnożenie razy 100 przez co można używać sond pomiarowych 100:1
What you attached it’s not a termination Z but an attenuator. For termination you need to install a Tee.
This is an honest oscilloscope. The performance / specs vs cost ratio is great. Again, great value for your money
It could be a feed through termination. I have several Tektronix feed through terminators - they’re better than tees because there is not even a short stub to create reflections - though at the maximum frequency usable on the 703S, a tee would be fine. I found about the same frequency response as Kerry on my 703S with the most current firmware downloaded from Zotek’s Google drive page point to from the Zotek product description page on their web site.