Old Analog Osciloscope with wrong voltage values on one channel

[augustol]

Hi, everyone,

I'm a beginer in electronics, have made a couple of projects by myself and decided to stop, study and dig a little deeper. Not much long ago I dicovered the EEVBlog on youtube and eventually the actual forum. This is actually my first post here But I've been reading a lot of the posts even before actually signing in and stuff.

So, I decided to get mysel an osciloscope. I was almost buying a Hantek usb osciloscope when I saw this old Minipa MO-1222 for sale. I decided to abandon the Hantek and get the old analog osciloscope.

It's a two channel osciloscope and i just received it. It came with two probes (wich I'll probably substitute latter). I decided then to do the basic testing using the 1kHz 2V pk-pk signal built in the osciloscope. Channel 1 shows the right horizontal scale but the vertical scale is off (it shows aproximately 1.4V).

Everything else seems to work fine, math function works ok, holdoff, trggering, level, coupling, etc. At least the things that I know how to check.

Channel 2 is also perfect.

Tried switching probes to check if the problem wasn't the probes and it's not.

What should I do?

[tunk]

Below volts/div there's another rotary knob - is it turned all the way up?

[augustol]

Oops haha

It wasn't. Good thing I posted to the beginners begginers section.

Thank you very much!

And yes, I will do a little research on what does that knob do.