Gibson G-3 Wiring Question

[jfspencer]

Hello there,

I opened up my '76 Gibson G-3 last night to diagnose a grounding issue and found some wiring weirdness for which I would appreciate an explanation. What are the white leads from the pickups doing taped up all by themselves? Are they supposed to be grounded? What are they?

I did not take a picture of it, but it looks pretty much like this: [Invalid or Expired Link Removed]

This schematic makes me think they should be grounded: [Invalid or Expired Link Removed]

The issue I am having is the old bass emitting a buzzing noise until you touch the bridge problem. Do you think it's the white leads? Could it possibly be a ground loop from the foil shield over the controls in conjunction with the solder on the tone pot? Does anyone else have this issue? Has anyone fixed it?

Thanks, y'all.

 

[line6man]

The schematic indicates that the middle pickup is in series with the neck and bridge, and the neck and bridge are parallel to each other. The white wires are the connections between the three coils. Take a look at the bottom of each of the three coils in the schematic. These wires should simply be soldered together.

The lines you see parallel to the coils in the schematic are the ground plates. These appear to be grounded normally, but the wiring is sloppy.

 

[jfspencer]

The schematic indicates that the middle pickup is in series with the neck and bridge, and the neck and bridge are parallel to each other. The white wires are the connections between the three coils. Take a look at the bottom of each of the three coils in the schematic. These wires should simply be soldered together.

The lines you see parallel to the coils in the schematic are the ground plates. These appear to be grounded normally, but the wiring is sloppy.

Oh, I see it now. Thanks, line6man. Now my question is shouldn't the bundle of orange leads from the pickups be directly grounded instead of tied onto the middle terminal of the switch? Doesn't that put them on the wrong side of the pots and caps?

 

[line6man]

Oh, I see it now. Thanks, line6man. Now my question is shouldn't the bundle of orange leads from the pickups be directly grounded instead of tied onto the middle terminal of the switch? Doesn't that put them on the wrong side of the pots and caps?

What do you mean by the "wrong side of the pots and caps?" The pickup selector switch offers the closest place to ground the pickups, and thus, it is the most efficient way to run the wires to the control cavity. The terminal they are soldered to is a terminal that is normally soldered to some other ground point, but the switch is getting its ground through the shielding. Some would prefer to run a wire from that point to the pots, because a soldered connection is more reliable than a mechanical connection, but that sort of grounding scheme is very common on many instruments, because it saves time and money.

 

[jfspencer]

What do you mean by the "wrong side of the pots and caps?" The pickup selector switch offers the closest place to ground the pickups, and thus, it is the most efficient way to run the wires to the control cavity. The terminal they are soldered to is a terminal that is normally soldered to some other ground point, but the switch is getting its ground through the shielding. Some would prefer to run a wire from that point to the pots, because a soldered connection is more reliable than a mechanical connection, but that sort of grounding scheme is very common on many instruments, because it saves time and money.

Okay, I did not understand the switching mechanism. Now I see that when the switch is in the neck position, for example, it is shorting the bridge pickup to ground to eliminate its signal path. Is that correct? Thanks again for your help.

 

[line6man]

Okay, I did not understand the switching mechanism. Now I see that when the switch is in the neck position, for example, it is shorting the bridge pickup to ground to eliminate its signal path. Is that correct? Thanks again for your help.

The ground has nothing to do with the switching. Is is simply to ground the switch chassis. The way those switches work is to disconnect the pickup that isn't being used. If you take a look at the switch, up close, you can see what it does in each position, since it is open frame.

 

[Matti Aikio]

Did You come up with any solution to the bad ground wiring problem? I have the same bass with similar problem, constant buzz untill you grab any metal part (=faulty ground wiring) wiring looks exactly like that one with the same kind of piss poor weldings (factory or McGyver origin??, no idea) Green ground comes from underneath the bridge and white appers to continue the ground into poth potentiometers (seems like home made?)

 

[40Hz]

If it will be of any help, attached are the schematics and wiring diagrams for the two ways Gibson wired the G3 (with thanks to Caedfel):