Hot Rod Deluxe with -20Vdc measured on the ground

[Jack1962]

anyone with any ideas why this Hot Rod Deluxe would have a measurable -20 at every point that should be ground potential on the main board 

[sluckey]

anyone with any ideas why this Hot Rod Deluxe would have a measurable -20 at every point that should be ground potential on the main board 

In reference to what? Chassis? Maybe a high resistance connection to chassis.

[Jack1962]

sorry I should have been clearer , from any cathode in the amp the cathode side of the cathode resistors a -21vdc can be measured .

[sluckey]

sorry I should have been clearer , from any cathode in the amp the cathode side of the cathode resistors a -21vdc can be measured .

In reference to what??? You have one meter lead on the cathode of a tube but where is the other meter lead? What do you measure if you connect one meter lead directly to one side of a cathode resistor and connect the other lead directly to the other side of that cathode resistor?

[Jack1962]

I have one end the black ( or common on most meters ) to the chassis ground , the other lead the red  one to either cathode on the tube or on the cathode side of the resistor I get -21Vdc . from the ground side it depends on which stage of the amp it's between -18 and -21Vdc . What I don't understand is no where (that I see anyway on the schematic or from inspecting the amp is there -21Vdc I see the bias voltage -50Vdc , the voltage for the solid state reverb + and - 16Vdc . I have attached the schematic.

[sluckey]

I have one end the black ( or common on most meters ) to the chassis ground , the other lead the red  one to either cathode on the tube or on the cathode side of the resistor I get -21Vdc .

I'm suspecting a poor ground connection on the pcb. May be caused by a loose connector, broken pcb trace, etc.

What voltage do you measure if you connect one meter lead directly to one side of a cathode resistor and connect the other lead directly to the other side of that cathode resistor?

Turn the amp off and measure resistance from the ground side of a cathode resistor to chassis. Should be zero ohms, but I suspect it is some higher value.

Is the amp sick? What are the symptoms? Do you trust your meter?

[Jack1962]

found the problem resistor R63 the 10 ohm resistor that is between the PCB and the chassis (well actually the ground loop on the pots ) was seriously fried. Thanks for the help Sluckey 

[LooseChange]

And how did that ^^^^^ happen?
Not sure that solves it... There should be a direct connection from the pc board to ground. Should be either to the right of the input jacks or dead center on the board. (Different models).