CATV cable signal level for tshooting

Hello,

  I have a new X1 box and a smaller digital box....new, never hooked up yet..   I am getting the looping Welcome screen which never connects..   I'm not really sure if it is my cable drops, but my modem connects to the internet fine if i put it on it.    

  I have received no help from calling support other than the typical I'll send a reset, but it will take 24 hours....I hate when they say that, it never does anything. 

I've left the box plugged in for days, with no change.

So the question,   Does anyone know what signal level (DBmV) I should see at the tap....and then what is an acceptable level at my Jack?   I literally bought my own cable signal tester since I do not have any faith in support to do its job.  (sorry support, but I hear the same thing over and over).

At least if I know what the levels are, I can check my own internal cabling.

Any help is appreciated in tshooting with a cable tv signal tester. 

Thank you!