Hantek 2C42 random pulses in roll mode

Equizer

I recently got my Hantek 2C42 and found out that in Single trigger mode scope just randomly triggers on nothing, showing a flat 0 V line or a voltage spike.

Later i dicovered that it happens even if coupling is set to GND, so i tried to take a better look at what's happening using roll mode and saw distinct voltage spikes happening randomly.



And there is another problem in roll mode, when channel coupling is set to GND, channel trace lifts up independent of vertical scale. So, for example at 100 mV/Div trace lifts to 52 mV, at 1 V/Div  trace lifts to 520 mV and so on.

  

But when AC or DC coupling is selected, trace stays near 0 V.



I would like to know why this is happening and how to fix it.
I assume this is due to errors in firmware and hope it will be fixed soon.

Equizer

Thank you for your reply!

amy

Yes, engineers are already working on this problem. We can get the result this week.

Equizer

Firmware 2019110801 problem is still there!
It's definitely an FPGA issue, I already sent you a video of my issues, can I at least get some feedback from actual engineers?

Equizer

Random pulses in roll mode when coupling is set to GND
https://filetransfer.io/data-package/waEo4Ycg?do=download

Random triggering when when coupling is set to GND
https://filetransfer.io/data-package/0NOc6xqx?do=download

Issues happen only on FPGA V04, everything is fine on V02
Upgrading/downgrading versions of STM firmware makes no difference.

amy

Please give me a video to study.

Equizer

It's not this specific mode I really need to use, it's just very clearly shows the problem that scope has. I use the scope mostly in single trigger mode, so I want it to trigger only on actual signal, not on some software errors. In V02 i can be sure that if I select single trigger mode, DC or AC coupling, and physically connect the probe to ground (or some line in low state) scope will never trigger. On V04 if I do that scope will trigger randomly on nothing and miss the signal.

OASJ2YSeeEhBQo1

Equizer replied at 2019-11-10 04:00
Software version 2019103001 nothing has changed, problem is still present!
I waited way more than a  ...

Now I'm curious, what are you measuring that you need so badly to use an oscilloscope with the inputs coupled to ground and set in roll mode?

Equizer

Software version 2019103001 nothing has changed, problem is still present!
I waited way more than a several days just to get nothing!

amy

I will test and feedback our engineer to modify.
We will update it in the next version. It may take several days.

Equizer

I think it gets worse when i increase time per division value, try to set 2s per division in roll mode and see what happens.