Fnirsi -TC3

[spanakop]

Whilst looking for a component tester, and I really couldn't be arsed to look through 342 pages of the form post, I came across this

https://www.aliexpress.com/item/1005005444684287.html?algo_exp_id=e871120f-2f47-4bb0-a9c8-658f6c5987f8-11

Fnirsi has released a new version of the their combi tool. It has a component tester, Oscilloscope and Signal generator all on the same package for around £40 including a 10x probe.

I'm interested in the component tester side of things rather than the Oscilloscope tbh. I see the other additions as a bonus feature.

has anyone had a play with this? They state the specs of the oscilloscope are upgraded from their last one.

[tunk]

There's a few reviews on youtube:
https://youtu.be/eBPtYV6tjBs
https://youtu.be/JpISM7g9Ff4
https://youtu.be/mAxUwG2US4U

[.RC.]

If you do not need the oscilloscope function, why spend such a large sum for it.

Fnirsi sell a component tester alone.   It has a fake chip on it marked Atmel328, but it is not even a clone, it is a completely different chip, so you can not as of yet customise the firmware.   However it is a reasonably accurate device, or mine is.  https://www.aliexpress.com/item/32795518755.html

Plenty of others out there as well.

[KungFuJosh]

I bought the TC3 expecting it to be a toy, that was maybe better than the TC1. It's a toy compared to a real bench scope, but the thing actually works.

I used it today to test caps for the outside foil, and it actually worked. Results consistent with the SDS2504XP.


The biggest downside of trying to use this as a scope + AWG (besides the obvious) is that the AWG only functions as a square wave generator (typical for probe compensation) when the DSO is active. You can't use it to send a sinewave to the DSO.

[Veteran68]

I have a TC3 as well. I think it strikes a good balance between the $7 component testers and the $50-$100 pocket scopes. Of course I'm not using it for serious bench measurements or signal generation, but as a portable tool for simple field work that I'm not going to lose much sleep over if it gets lost or destroyed, it's great.

[slavoy]

I've tested the TC3 for a while. Overall, it's OK, with a clear menu and plenty of functions in one device, although their usefulness depends on the parameters we expect. The component tester made a mistake once, showing a P-MOSFET instead of a PNP transistor. As for measuring capacitor ESR, the results are not accurate and, in my opinion, not reliable. Apart from that, everything is fine. Some report that it's easy to damage them with overvoltage (especially the earlier TC2 version), so it's essential to be cautious and discharge capacitors before measurement. The same goes for the measurement socket's polarity - better not to make a mistake. The built quality is decent. The generator part is very limited and the scope has little above declared 500kHz bandwith. No isolation whatsoever, so be careful with high voltage measurements by the scope probe.

[siealex]

The component tester made a mistake once, showing a P-MOSFET instead of a PNP transistor

Did it show "enhancement mode" or "depletion mode"? Some component testers confuse some types of BJTs (especially germanium) with JFETs or depletion mode MOSFETs.

[KungFuJosh]

You're 100% correct, it certainly has its limitations per its specs, but that's exspected. A limitation with the cap test I was doing is that it doesn't go below 10mV, so I couldn't use it for all the caps I was testing. But it was still nice to see it actually works well enough for its stated range.

[picburner]

Besides making mistakes with active components it also makes mistakes with passive components.
In the picture you can see how a mosfet P is invented from a 4.7 uF tantalum capacitor.
The funny thing is that it happens with particular capacitance values.
Another user of this forum, in another tread, noticed the same effect with 10 uF ceramic capacitors.

Capacitor value is 5.680µF if placed between terminals 1-2. If placed between 1-3 the bug also shows up with other values (5.412µF, 5.430µF).

[slavoy]

Interesting. Perhaps another firmware bug? The TC3 has the ability to update (one update has already been released), so it might be worth informing Fnirsi about this issue.

[KungFuJosh]

Interesting. Perhaps another firmware bug? The TC3 has the ability to update (one update has already been released), so it might be worth informing Fnirsi about this issue.

That's cool, I didn't expect to see updates. They can be downloaded here through the firmware tab: http://www.fnirsi.com.cn/download/digit

It's all in Chinese, but pretty straight forward expect the apply button is just the right area of the dialog box, and not clearly a button.

It's odd that I can't find a screen that shows the current system info.

[siealex]

In the picture you can see how a mosfet P is invented from a 4.7 uF tantalum capacitor.

Usually these testers see a tantalum capacitor as a diode with the corresponding capacitance in the reverse direction.

[slavoy]

The component tester made a mistake once, showing a P-MOSFET instead of a PNP transistor

Did it show "enhancement mode" or "depletion mode"? Some component testers confuse some types of BJTs (especially germanium) with JFETs or depletion mode MOSFETs.

It was KSR2004 PNP transistor shown as P-MOSFET in TC3. I compared it with the GM328A tester and it recognized the BJT correctly.
I think the TC3 needs slightly better firmware. Inside, there's an ARM Cortex with USB support, so it has a lot of power. The TC-X and GM328A testers use simple 8-bit ATmega chips, yet they offer impressive capabilities, thanks to the well written code.
I forgot about the built in Zener diode tester (32V max) - very handy.

[picburner]

It's odd that I can't find a screen that shows the current system info.

The screen with the system info is the one in the picture.
Press and hold "OK/Menu" for a while to get there.
Unfortunately my firmware is the latest available.
I hope the manufacturer fixes these bugs because overall, considering its category of price, the instrument isn't too bad.

[KungFuJosh]

Thanks! That's good to know. I think they'll fix the fixable bugs eventually. I turned off the logo in there, now it starts up faster lol.

[LinuxHata]

I had this, it was making too many errors so I gave it to a fellow student.
Very often it will measure single coil inductance of relatively high value (1mh and above) as an IGBT transistor

[KungFuJosh]

I had this, it was making too many errors so I gave it to a fellow student.
Very often it will measure single coil inductance of relatively high value (1mh and above) as an IGBT transistor

I consider it a toy, and toys are fun. 😉 But it's cool that it can actually do some stuff.

I haven't found a spec sheet, I wonder what it claims it can accurately measure for inductance.

[Aldo22]

I haven't found a spec sheet, I wonder what it claims it can accurately measure for inductance.

[axantas]

I used to use the TC2, which had a strange interface, then got the TC3 a chance. I am doing a lot of old analog restoration stuff, sometimes just checking, whether one of the components are dead. Indeed it "identifies" components erroneously at first try, but knowing, what I am inserting, it is just "try it again" and it does its job. I double check every now and then parts like capatitors with a multimeter - getting identical results.

So as an inexpensive all-in-all ting, I am quite satisfied with it. 

[KungFuJosh]

I haven't found a spec sheet, I wonder what it claims it can accurately measure for inductance.

Thanks! That spec sheet either isn't accurate, or there definitely needs to be some more firmware updates. I would guess both. 😉

On my reference board I had no trouble testing 1mH, 10mH, 100mH (1mH is the max on the spec sheet??), but I couldn't test anything lower than 1mH. R and C were both fine for what's in spec, except I couldn't test 100pF.

[siealex]

Today I received a new motherboard for TC3 and installed it into my TC2. In general it works properly, however, there are several strange bugs.
1. Generator. The output frequency is exact only in Square and Pulse modes, in other modes (sine, triangle, sawtooth) it's way off, up to 2%, and changes only in large steps.
2. Oscilloscope. On high voltage ranges (1 V/div and higher) in DC mode the zero line is off by 100..300 mV in a random direction (depending on the range), usually up. Can this be adjusted?
3. Oscilloscope. Low time per division ranges (5 μs/div and less) have incorrect X scale. For example, a 500 kHz wave on the 2 μs/div range must be EXACTLY 1 large box wide, actually I see 14..15 waves per 12 boxes. A 100 kHz wave on the same range must be 5 boxes wide, actually it's 4 boxes (is it 2.5 μs/div???). The 10 μs/div range seems to work properly.
4. Voltage. There is a calibration mode with two points: 5 V and 20 V. After calibrating (using AD584 for 5 V and a step-up converter for 20 V), it displays 5 V, 7.5 V and 10 V correctly (+/- 5 counts), but 2.5 V is 1% off (high). Why?

[solidhit]

I just received my TC3 today. The ESR meter is completely broken and always produces false results. I wonder, all those YouTube reviews and no one found the ESR meter doesn't work! 

[indman]

solidhit, Don't trust Youtube reviews! Fnirsi DSO-TC2 and DSO-TC3 are toys in a beautiful case, nothing more! Isn't this clear?
I can’t say anything good or bad about the operation of the oscilloscope, since this functionality with such funny parameters interests me little.
It is of little use as a component identifier since the original code of the respected Markus Reshke and Karl-Heinz Kübbeler was transferred to the STM platform very poorly. Therefore, you cannot trust such a device to check components, and this is confirmed by many owners of these toys. And the resistance can be measured successfully and with greater accuracy with a conventional multimeter.
Here is one of the few examples of measurements that I posted in an extensive topic '$20 LCR ESR Transistor checker project"
https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg4785317/#msg4785317
https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg4785317/#msg4786418

[solidhit]

Can anybody provide me with v0.2 of the firmware as I cannot find it on the official page? Just to verify the problem I have with the ESR meter has nothing to do with my present firmware version (v0.3).

[kru.czekdb]

Hello, I damaged my dso tc3. charged capacitor 😔 I replaced u6., it works but I don't want to calibrate. can anyone help?