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Hantek 6022BE 20MHz USB DSO

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horo:

--- Quote from: raxis13 on July 16, 2019, 06:03:33 pm ---I am very happy to have some to troubleshoot an old radio TSF.

--- End quote ---

Hi Raxis13,

Nice historical radio, but due to high internal voltages also a bit dangerous. I started my electronic experiments many years ago with gear like this - been there, done that :)
Just out of curiosity - what kind of measurement tools do you have at hand when working with tube radios?

Regarding the Hantek scope, please keep in mind that the usable input voltage of Hantek6022 is limited to ± 5 Volt (voltages outside this range are clipped and the channel name in the bottom lines turns red as a warning (as seen in my screen shot some posts up). The input (at the BNC plug) shall never exceed ± 35 Volt to avoid degradation or damage.
Supplied with the scope are two probes that can be set to X1 or X10 mode, the later setting allows to measure ± 50 V signals (with ±350 V safety margin). For higher voltages a X100 probe can be used but these are expensive.
Another possibility for measuring smaller signals with a high DC bias (as usually found at the anode of the nice dusty tube on the left in your 2nd picture) is to create an AC coupling (that's unfortunately missing in the Hantek in order to spare some ct in production) by connecting a small (~10..100 nF) plastic film capacitor in series to the tip of your probe, this capacitor should have an operating voltage > 500 V to be on the safe side. With the open end of this capacitor you can touch the interesting points in your radio, wait 'til the trace (that has jumped to the top) comes to the center again and stabilizes and then measure the AC while the capacitor blocks the DC offset (it charges itself to the DC voltage within seconds, so you should discharge it (easily done by touching the metal frame of the radio with the open end for some seconds) before measuring at different levels or touching by hand to avoid the painful (but not lethal) electrical shock.
Another thing to remember to avoid damage to your computer and scope is that the scope's GND signal is directly connected to your computer and via the computer's power supply a connection to the earth potential of the mains exist. So _never_ connect the probe's GND clamps to any other level than the GND level of your radio. (This limitation is found in most scopes, even in the most expensive ones.)

Have fun
Martin

raxis13:
Hi Martin,

This TSF comes from my family.  It can be dated from the 1920s. 
I recently discovered that my son-in-law who works for an ISP is very interested in old radios, but he does not have one, and does not know about my treasure. So I set myself a real challenge: repair it, and offer it repaired for his birthday. But I only have a multimeter. I documented myself. But first size difficulty encountered: I located the fault upstream of the frequency change stage, but I'm not sure. The only way to find out is to use an oscilloscope. By dint of research, I discovered the card Hantek6022BE which has just the necessary characteristics, except as regards the input voltage. So I bought a probe x100 (9,59 € shipping price included by internet ; out of the forum, if you want i could give you the address), and I received it yesterday. I immediately tested the set: the Hantek6022BE card, the probe x100, and especially your software, that i now know how to use thanks to your message of yesterday. Everything works perfectly. Thus equipped, I will be able to measure the frequencies present in the different stages.
Indeed, it is necessary to take great precautions for oneself (risk of electrocution by propagation of the HT by the mass to the Hantek metal case) and for the equipment (HT input on Hantek6022BE, and PC) during interventions.  Moreover on this TSF not only the high voltage (350V peak) is present, but it is equipped with an autotransformer. So one electrical line (neutral or phase depending on the connection to the socket) is connected to the metal chassis of the electronics.
As protection :
- i used a portable PC (electrically separated from domestic 220V grid), and not a fixed PC
- i wear plastic gloves
- i use x100 probe

Thank you Martin for your always good, and very precise advices.  I particularly noted your method for measuring weak signals.

Regards.

Raxis13

horo:
Hi,

During the development of the latest free open source firmware I drew a quick sketch of the 6022BE schematics (with 6022BL differences noted in green). I took a deeper look at the digital back end - the analog front end was already documented by RichardK, I merely added the pinout of the ICs. RichardK also analysed the power supply circuit. Both schematics together with RichardK's comments should give the complete insight.

CU Martin

Cliff Matthews:
Just downloaded OpenHantek-Win-x64-Release-b66.zip (trying to stay away from late beta or bleeding edge zips)
On my Intel i5 system with win-7 and 8g ram, default 1.06 Hantek SW works great on FP USB3 ports.

I unpacked b66 to a folder and ran VCredist_x64 fine, but when running OpenHantek.exe I get upload in progress for >30mins..
I suppose it's uploading firmware to the cypress chip?

horo:
No fear, this device cannot be "bricked" as the firmware is not flashed but only uploaded into RAM (there is no flash at all) where it stays only as long as the device is connected via USB. I got the info that sometimes on windows the very first upload doesn't work properly. Just cancel and restart (without disconnecting USB).

Martin

ps: the "bleeding edges" on github are mostly bug fixes and little improvements that do not yet justify a new version number, the real feature development is done in own branches on my computer and is never uploaded to github. So it's always safe to clone the master branch - the latest commit e.g. improved the readability by defining better default screen colours and fixed also a possible divide by zero (that didn't harm at least on linux).

pps: you can examine the firmware on https://github.com/Ho-Ro/Hantek6022API

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