Fender Concert pot bracket resistor

[fuzzman72]

Hello

I'm troubleshooting a Fender Concert Reverb reissue for a bad and noticeable hiss.
I was looking at the schematic (see pics) when I noticed that there are some 10 ohm resistor from the pots brackets and ground.
Since the brackets are in contact with the chassis, they are already at ground potential.
I really can't understand the function of these resistors.

By the way, the resistor R83 between J6(power amp in) and ground is burnt.

[Jazz P Bass]

I think the 10 ohm resistors are a way of seperating the power grounds from the signal grounds.

[Enzo]

R83 burnt? SOmeone pl;ugged something into the power amp in and it was not well grounded. Lots of current went through the resistor looking for ground.


Look at the mains cord input, see the ground ssymbol? I call that a "rake" myself. Note that the grounds you have referred to use the triangular three line symbol. We call that "ground" also, but in reality it i snot ground, it is the circuit "common." Now look at the input jack. We see it has a connection to common, AND right there is the green wire to chassis. That point is where chassis and common join.

The 10 ohm resistors? They insure a low resistance path in the even a jack loses contact with chassis.

Pot brackets are already in contact with chassis? Not, I;d wager, when the board is out of the chassis during service.

[woodyc]

I think the 10 ohm resistors are a way of seperating the power grounds from the signal grounds.

I vote the 10 Ohms are to limit ground current when you have a grounded effect. Because the grounds can differ by a few mV ac even if they are plugged in the same outlet.