Just have received the thing. Board 9.15, firmware 1.3.0C. Some observations and bugs discovered.
1. The AUTO function doesn’t detect the waveform below 7 Hz. So, if the screen covers the wave only partially, the frequency cannot be displayed. Manual timeline setting should be used.
2. In two channels mode sometimes after the frequency change in one channel the displayed value and the waveform are completely wrong. For ex. when the wave frequency (meander) is 2 MHz, the shown value is 2,29 Hz (!). If I adjust manually the time value, the waveform changes and the displayed value becomes correct.
3. The saved images may change after the capture! If I save a screen with a box over (for ex. when frequency adjusting), the value in the box will be replaced in all saved images with the last one. It looks fantastic, but I rechecked the issue, the oscilloscope changes saved images.
4. The generator makes good waveform shape, but the frequency is not very accurate. In the Hz range the generated frequency sometimes is 10-15% over or under the selected one.
To note that although the last digit changes the frequency, it cannot be saved and is rounded to the previous one.
5. DC detection is not accurate as well. The difference between the values when the polarity changes grows with the vertical scale value. I calibrated the 0 many times, the best results were obtained when the both channels closed and set to the x100 (probes off). However if the 8,25 V battery at 2.00 V per div. shows +8.33 V and -8.54 V, at 10.0 and 20.0 V per div. it shows near +8.00 -9.00 and +7.50 -9.60 V respectively. My old CRT oscilloscope shows it correctly, regardless of polarity. May be nothing to do with one polarity supply scheme, but one should pay attention on it.
I understand that this model is pretty over, but hope that my observations will be useful not only for its owners but also for the developers, if one could transfer its to them.