Longtime lurker here.Finally registered.I started with an rm80 over a year ago and now have 2 rm100s.I'm no stranger to biasing these amps.I just swapped tubes and went to bias and got a reading of 00.0.I changed the batteries in my multimeter and bought another multimeter just in case.Still no reading.When I put the red test lead in I start to get a reading then it ends up on zero.All tubes are lit up.Is there a fuse for the bias points.Anyone ever have this happen?For the record I did about 70 gigs with these amps and other than a tube blowing have had no problems.Any help is appreciated.Great forum!