/diy/ - Do It Yourself

I recently got an old dual channel analogue oscilloscope for really cheap (Philips PM 3260). While channel A works alright from what I am seeing, I am not getting a trace for channel B. I read an old tektronix guide for troubleshooting, which told me to "milk" the front panel and all the buttons to see if I could determine what is wrong from there. I tried every setting that I could to try to get a trace or dot to appear on screen (I don't think that this scope has a beam finder button on it, so I don't really have a way to check if anything appears on screen), but was unable to get one to appear. On the front of the scope there is an LED that turns off when the scope is triggered, and when I applied the channel b probe to the test point or put my finger on the probe I was unable to get it to go off.

Because of this, I have (possibly wrongly) concluded that the issue with channel B is in the attenuator stage, mainly because I can not get the trigger light to go off, even when I set the trigger to channel B. Does my diagnosis sound correct? I feel somewhat weary of it, since I don't have experience with oscilloscope troubleshooting.