Hello everyone,
I just purchased a 60MHz dual trace scope (a Sampo SSI-2360 to be specific) which I thought was working. Unfortunately, it appears that it is not quite right. I was hoping somebody could point me in the right direction with fault finding it. With the inputs grounded, I can get fairly focused traces, but not particularly sharp. The scope triggers fine and the vertical amplifiers seem to be working perfectly. However, if I connect the input of either channel to the calibration square wave then I can get a semi-square displayed but the trace seems to be "smeared" so that the high and low parts of the waveform overlap. It's hard to explain so I took some pictures:
Playing with the focus control will give me a waveform like this:
The waveform looks exactly the same on CH1 and CH2, and any timebase setting, so I suspect a problem with the HV section? My experience is mainly with digital electronics so I'm not sure where to start. Can anyone please offer some advice?
Thanks very much for any help, Dean