"THo" wrote in message
news:iKqQd.398480$8l.64298@pd7tw1no...
I was given an old oscilloscope, and I'm not sure if it's working
properly.
It's a tube-based one, Tektronic 515. There's only one probe with it, and
I
connected it to a radio, and it does respond, somewhat. But when there is
no signal of any kind, the image traced on the screen isn't a moving dot,
it's more like a band, and no matter how it's adjusted the band never
moves
more than halfway across the screen. I've attached a pic of the output
when
there is no input of any kind. How abnormal is this? Is there a way to
re-calibrate it or anything like that?

Tom


No.
This is not normal. It look like a sawtooth waveform from a sweep circuit.
Sorry, I am not familiar
with this model. Does it have any built-in scope calibrator? Many of their
even cheap scopes have
a built-in square wave generator. This allows you to set the waveform
amplitude and scope probe
frequency response (capacitance). I realize that this isn't much help. Why
don't you contact
Tektronics?