Cary 805B without bias pot

The Cary 805 series was never designed with auto bias.  If in doubt, go to the Cary website and look at all the various 805 manuals and they all have a section on how to bias the tube.  To check yours, plug in the bias meter and turn the bias pot and see if the bias changes. 

Well, if your 805b amps do not have a chassis cut out hole for the bias pot or the meter jack, I would hazard a guess that your amps are a prototype of some sort.  If they were upgraded/modified, they would still have the chassis cut out holes.