yaqin bias pot problem

I just got a used yaqin MS-20L and then went out and got new tubes.  I've watched all the youtube videos on how to set the bias. Problem is when I put my meter in the pots I'm getting .007 or .008 and all the ports I test. what am I doing wrong? meter is in the + and - slots, tubes have been up for 1 hour or longer. Meter is a very good one. Please help me out.