This post may be a little retro, but I am sure some other folks are looking for some basic info on the OWON SDS7102
To the OP.
1) Note the scope has 400V printed right next to the BNC connectors on the front. What is the plate voltage of your power tubes?
2) Connect the probes to the scope and then onto the appropriate test points..... be sure you ground it to the ground test point on the power supply.
3) The [AUTOSET] button is your friend.
