This is my first scope and I picked it up for about $50 total. The picture in the auction below shows a trace but when I got it, I'm not having so much luck.
When I turn it on I get a red power light and it is otherwise perfectly silent, no sound, no HV hiss. I've got pretty good hearing though. I can normally here the high pitched sound of a muted TV from another room.
I turned the intensity up all the way and still nothing. I fiddled with the knobs and switches and when I was about give up, I turned it off and the screen did a quick green flash.
I turned it back on and got a trace that traveled about 2 divisions, made a slight pulse of about 2 divisions tall, then another that was 1 division tall and then one that was about .5 divisions tall and then blank. This all happened in about 1/5 of a second.
I turned it on and off 3 or 4 times and could occasionally get the blip to repeat.
I fiddled with the knobs and switches again and now I can occasionally get 1 dot to appear for about 1/4 a second stationary, then travels about 2 divisions to the right in about 1/2 a second then disappears.
I'm not familiar enough with scopes to know if this is indicative of a specific failure or something else.
I took the lid off and found a 4 pin cable going to the main board that looked about half cocked. I pressed it down but it didn't change anything.
I have the manual with schematic if that helps.https://docs.google.com/file/d/0B3nYGMOtVmrVdEVSd1U4dlRxMjQ/edit?usp=sharing
I'm going to try to make a video once I can get enough light. These 60W equivalent CCFL lights in my apartment aren't very good for filming.http://www.ebay.com/itm/Tenma-oscilloscope-/300937689970