I found this link, did not test it though drive.google.com/file/d/1Sd3YS1RNme_9VrY4SYDEce5mHvTl5e_G/view Claims to be ZOYI-703S-FW-V142(1).ZTK

great video! being a similar age to you I dont mind the nostalgia🙂

What is max length of FFT it supports? is it possible to change it at all?

My childhood was very close to yours... at school, the kids who had multimeters were almost considered "the test equipment gods"... and the rest of us dreamed of being as cool as they were one day... oscilloscopes? they were the sort of things you'd find in laboratories. :) ❤❤❤E.T.I. ❤❤❤

If you search for zoyi703 firmware on Google and open the firmware page directly, you will see version 1.3.9, however, if you search for zoyi 703 on Google and enter the Zoyi page where I believe the device is sold, then there is a yellow button that says software update, you will see version 1.4.2.

If you reduced the 555's frequency to be half the scope's sweep frequency you could have it display the pure signal for each channel on alternate horizontal sweeps. A bit like interleaving on a TV screen.

Out of interest, what were the original spec,ed transistors?

Hi Bill, it seems that this circuit is running in chop mode. On the old two channel scopes, one could chose between chop and alt. Would it be possible to change the circuit in a way to replace the 555 by some sort of flipflop to be flipped by the trigger signal? Or turn the 555's frequency all the way down so one cycle spans the whole screen?

Regarding your Zoyi scope - does it have a "dot" mode? Some digital scopes have a dot versus "line" mode for rendering the traces. Perhaps the dot mode would remove the vertical stripes and make the Zoyi look more like the Hameg's output. My own scope (a low-end Keysight) doesn't have this dot mode, but the one at my old job (a Tektronix) did. It'd probably be found in either the display menu or the acquire menu perhaps.

What's that oscillation on the low part of the waveform at 9:37

and one more question, what was the final switching frequency?

it would work just fine if you set the scope to point and not vector display, my dso2d10 can do it , the problem is even if we ignore quite low switching frequency the digital bandwidth of a scope would be cut in half similarly to sharing one adc to 2 channels

What would a square wave and sin wave look like.?

A trip to memory lane: I had/have a 3-way splitter from ELWE called isolating amplifier switch: banaplugs for input, with knobs for adjusting position, height and (very important) on which signal you want to trigger. You could even adjust the 'chop' frequency. Works great on analog scopes, not so great on digitals. Thanks for this nice video.

That’s cool 😎

I tried building one out of 4066 but didn’t get it to work. That was many many years ago.

I personally don’t mind the nostalgia. Tech stuff is everywhere, but personal stories are unique. Thanks for taking the time to do this

Great video. I fully understand your nostalgia and it reminds me of my younger days... dreaming of an oscilloscop!

Wonder how this would work on one of those awful cheap digital scopes....

Hi Bill, I want to ask you a question. Where could we use this circuit in a real world application? Please excuse my ignorance, im very green to electronics and i just want learn.

Very interesting. I'm sure many a hobbyist built one back the day when test equipment was so expensive. Thanks for the video Bill.

Hi Bill, I've learned more about electronics from watching your videos than anything I've read. Im 54 and always learn something new from your video's

have an auto shutdown problem. After update With the new version, Mom still shuts down as quickly as before. Looks like it only opened for 1 minute. How should I fix it?

Thanks for another very interesting video Bill. Explained and demonstrated really well. All the best.

Thank you for the great demonstration 😊

Thank you very much for your great video!!!!!! I'm a beginner and I was wondering if you could tell me how many amps I need to set on my power supply for the breadboard low pass and high pass filter. And also, if you could tell me where to hook up the signal generator!!!!!!!! I really like all your videos!!!!!I'm from Northern Ontario, Canada. Thank you

I'm just taking a break from writing one short crappy blog entry and that's made me think about the amount of work you must put into making each of these videos and I thought I'd pop by the comments section to say thanks for all the effort. :)

Thanks for that, i think that you M1 marker are a bit off peak in the phase noise meas

What version is this? I see v1.39 and v1.42 on their website under different locations which is confusing...

I couldn't find the update ver. 1.4.2. The latest version now is 1.3.9. Maybe the 1.4.2. had some issues and it's no longer available... Somebody knows the reason why it disappeared?

Thank you! This is a very welcome distraction from our elections here in the US. Looking forward to the next video!

Now I have too spend money

Thanking you most kindly from English England

Quartz Crystal Oscillators are in my opinion the more stable circuits. The 32.768 KHz is my favorite. Reasons are it’s divisible by two.

Awesome video thanks Bill

I like your little scope with a curve tracer built in. Very nice.

I am going to build an optical theremin with this. Aliexpress sells these.

Can I obtain some information about the frequency span and dB values from the scope? So far, it's only a nice picture but it would be interesting where the peaks are and what the signal strength is there.

What is the input voltage on second circuit ( common emiter amplifier) Thank you

So I take it that the choke under screen no longer needs replaced now, and neither does the supplied capacitor?

Pushing the FFT button also switches between channels, ch1, ch2 or off

Thank you! Super!

Hey, thank you for enlighting me with LEDs :) I have a few questions and would be thankful if someone has the time to answer or a link to noop understandable resources: In the end, you convert the NAND Gate to a NOT Gate by connecting the inputs. But isnt it the same as the Inverter in the first video then? beside, that it needs mor components? or whats the difference? Secondly, what should be the value of the pullup and pulldown resistors, when i want to drain it with 6 or 8 Volt. Third: Can I controll it with 10Vpp Gates or even 20Vpp Gates (+10V to -10V), when I'm just draining it with less voltages like 6V? and last: When I gate it not with gates but with sinoid LFOs. where does it switch? Or whats the term to look for in the datasheed, which discribes the switchin threshold. If someone is interested to build also XOR, XNOR and OR Gates, here is a good resource.... www.allaboutelectronics.org/cmos-logic-gates-explained/ kzbin.info/www/bejne/nGTdg61mmZ6Ld5o&ab_channel=ALLABOUTELECTRONICS but sadly it didnt answer my question, or I havent understand it. btw.: thats very nice in your video: it's easy to follow as a beginner!

Really interesting series, thanks a lot. Looking forward to the next one.

Love this series! Oscillators are fascinating! The parallel circuit photo seems to be missing the 82k resistor. The output still looks great, so I guess it's not needed. Keep up the great work! Thanks!

Great video on oscillators. I noticed that in the parallel oscillator you used a resistor in place of the inductor in the drain of the JFET . Any specific reason for this?

I tried to upgrade to 1.4.2 version...but it is still appears 1.3.9 version....

Yes, it's an octopus, though they're marketed as a curve tracer.

Thank you for the detailed information! Love to see the Siglent arb-gen (awg) and scope.

That's a nice little video! Very cool. I loved how you used google translate to read the directions.