How to bias a tube amp with a Multimeter

^^^ Thinking about what he's saying..Try backing one of the + screws out & see if it comes all the way out or has a stop point..If it has a stop point move the ground screw out as well & retest,you never know...

@larryi @freediver thanks for your suggestions. I will try adjusting the MM, and the screws on the amplifier tomorrow to see if I can get a reading. Thanks for your assistance!

Here ya go!

https://www.galvinpower.org/bias-tube-amp-with-multimeter/

Measure the resistance at test points + and - with the amplifier powered off. If you cannot get any resistance readings, you cannot bias the output tubes.

If this is the case, the problem may be a bad meter probe or the amplifier test point is not connected to the cathode resistor.

It is easy to check the meter probe--just touch the two together when testing conductivity or resistance.  Probes are often pretty cheaply built and the wires, because they are constantly being moved and stretched, often do break.  That is a good observation of possible unexpected problems.