New (toy?) DSO, Fnirsi-138 Pro: 2.5MS/s, 2.4" screen

[tunk]

New pocket DSO from Fnirsi:
- 2.5MS/s, bandwidth 200kHz
- 2.4" screen
- with or without battery

A youtube review, saying the real bandwith is 50-100kHz: https://youtu.be/c7s6_YIaUJc

Fnirsi "official" store on aliexpress: https://www.aliexpress.com/item/1005003839624513.html?spm=a2g0o.store_pc_groupList.8148356.5.24c3718bE1TX09

[Fungus]

Looks like a repackaged one of these:

https://www.aliexpress.com/item/1005003666640863.html

They're horrible. Not so much the 'scope (what do you want for $20?) but the user interface. 

[Brumby]

I picked up a JYTech DSO138 as a kit (like the one Fungus linked to) so I could get in some SMD soldering and have something useful as a result.  (There are clones and fakes out there and JYTech were keen for people to know how to tell the difference.)

The UI is awkward, but it does work as a scope.  It is limited in what it can do, so don't expect anything serious from it and you won't be disappointed.

I did use it in anger once for a situation where I nothing else I had could do the job safely.  I wanted to see the operation of a certain signal (around 5V amplitude) in a circuit that floated at a couple of hundred volts - so I powered it from a battery, attached it and set it up before applying power to the DUT.  It performed perfectly for the task ... as a fully floating scope.



One day I might spring for some differential probes.

[tunk]

A very short review and a PCB photo here:
https://www-ixbt-com.translate.goog/live/instruments/fnirsi-138.html?_x_tr_sl=ru&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=sc

From the video and link above it uses a WCH CH32F103C8T6
which is a 72MHz Cortex-M3 SoC with 64k flash and 20k RAM:
http://special.wch.cn/en/mcu/

According to this datasheet the ADC conversion time is 1us
(run through google translate), so the 2.5MS/s claim may be inflated:
http://www.wch.cn/downloads/CH32F103DS0_PDF.html

[pcprogrammer]

According to this datasheet the ADC conversion time is 1us
(run through google translate), so the 2.5MS/s claim may be inflated:

Most likely a clone of the STM32F103C8, and if so it has 2 ADC's. When used in interleaved mode they can get 2MSa/s. Still a bit lower then 2.5. But we know FNIRSI is not shy of lying about the capabilities of the equipment they sell

By the looks of it, and already stated by Fungus, it is very similar to the JYEtech scopes. I have a wave 2, the 2 channel version and don't like it due to the restless screen. When measuring it flickers quite a bit.

[Oilngas]

According to this datasheet the ADC conversion time is 1us
(run through google translate), so the 2.5MS/s claim may be inflated:

Most likely a clone of the STM32F103C8, and if so it has 2 ADC's. When used in interleaved mode they can get 2MSa/s. Still a bit lower then 2.5. But we know FNIRSI is not shy of lying about the capabilities of the equipment they sell

By the looks of it, and already stated by Fungus, it is very similar to the JYEtech scopes. I have a wave 2, the 2 channel version and don't like it due to the restless screen. When measuring it flickers quite a bit.

I have a Wave2 and updating the firmware to 113-15801-080 from the JYETech site largely reduces the flickering issue.  I see that the latest firmware is now 113-15801-092.