Need schematic Gibson GA20RVT Minuteman

[gapcity]

I am in need of a schematic for the 4.3 volt heater circuit on a Gibson GA20RVT minuteman amp, there are two resistors, one on each line of the heater circuit that were grounded to the chassis at the same point at the end of the line, both were burned completely through and are unidentifiable. The Gibson schematic does not show this circuit. Perhaps it is a standard resistor that any tube amp tech would know, but I don't.

[T9c]

This should help. Take a look here: http://www.ampix.org/albums/gibsonamps/ga20rvt.pdf

(R38 & R39)


Rick

[RWood]

(R38 & R39)Rick

+1

Note that your replacement resistors don't have to be 100 ohms but they should both be well matched to each other, otherwise the ground will be imbalanced and you'll get some hum. So, for instance if you had a bag of 150 ohm resistors, and you found a pair that were within an ohm of each other, you could use them.

An alternative would be to use a 330 ohm or so variable resistor, connecting each outer leg to the heater supply and the wiper to ground. Then you could dial in your own balance by listening for the least amount of heater hum.