My First Oscilloscope - A question about calibration

[JoeNewberry]

I got my first oscilloscope today. Nothing particularly fancy, but at $25 the price was right. I figure this will be a good scope to learn on. It's a 50Mhz Hitachi V-550B.

Now, the problem is that when I touch the probe to the .5V calibration tab, that's supposed to generate a nice square wave, I instead get the waveform I have attached. Does anyone happen to know what part of the scope I need to adjust to correct this? Maybe a simple pot or set screw I could turn to fix it? I found the operation manual here:

http://www.hdeg.tzo.com/004%20%20%20...ion_Manual.pdf

It has schematics of the whole unit, but no mention of what to adjust to bring everything into proper alignment. Someone is selling the service manual on eBay for 40 dollars and that seems a bit excessive. Any ideas?