Could you please confirm that your twisting of knobs also included a setting of 200 mV/div and +8V bias voltage? What voltage did your multimeter show on the scope input jack in that state?
I'll do it after 2N3055 explains to us how measuring a voltage across something with a 1MOhm impedance has any significance.
FWIW I measured the current across the connector with those settings and saw 80nA.
Does that answer the question?
No it does not.
And 80nA will fully open MOSFET or FET if enough voltage is available and create all kinds of problems. Fact that you don't work on high impedance circuits does not make it non problem for everybody...
Tom already confirmed that DHO900 behave the same ...
And to answer your other post, yes I am eager to find the truth..
As a service to my fellow Rigol users.. I don't care if DHO800 has defects because of me.
I'm not in a market for one, I would be more interested in DHO4000 series as a type of product.
Inexpensive does not mean cheap nonfunctional shit. DHO800 is limited enough in capabilities that it's price is very good only if it works flawlessly.
Who's side are you on? On your side and all other users and demand best product for your money, or you work for Rigol hiding stuff?
I actually think Rigol is decent company and all problems are there because of rushing to the market. Given the chance they will do you right and fix the stuff. But nobody ever fixes problems they are not aware of...
But hey, it might just one more of those imperfections that are simply showing it is entry level instrument and what is its price range.
Maybe I expect too much.
But this shows that sometimes you need to pay more to get more...
On SDS2000X HD I can have
80V offset on 200mV/div range. And it shows full 140µV on input in that case... yes 140
microvolts. That is
worst case scenario. On average it is 20-30µV.