JE-1200 1H (something's wrong)

[GuitariSteve]

Hi,

Actually this thread isn't for me but for a friend of mine.

So he's got a JE-1200 and a J-50BC. It's a 1H guitar with only one volume pot.

He soldered the J-50BC a few weeks ago, everything was alright. Then he's tried to solder the JE-1200 this way:



...except the fact that he's removed the dark brown cable.

Here are the main issues:

- No sound.
- The battery is heating (this happens very fast).
- There is this annoying "bzzzzzz" noise when he touches the cables or some parts of the JE-1200 while testing it.
- When the volume is completely turned up, the "bzzz" becomes louder than when it's turned up half-way.

I hope you'll be able to help him,

Thanks!

[dg]

I think his problem is with his ground wires. On my guitar with the JE-1200, nothing is grounded to the onboard volume pot. I have a central ground point where my bridge, pickups, tone pot and the terminal on the board that he has wired to the volume pot all go (the top one of the three at the lower left corner). I believe there is an internal connection on the board that then routes the grounds to the terminal that is then wired to the jack, so it's not necessary to do anything but have that central ground point. I think what he may have done is somehow created a dead short by grounding to the volume pot, since it is connected to the circuit board. Have him remove all the wires from the volume pot body and wire them together at another point, like wherever his trem claw or bridge ground wire is connected.

He basically needs to combine these two diagrams and eliminate the tone pot from the circuit:

http://audiozone.dk/cm/displayimage.php?album=66&pos=14

(black & green in this diagram are reversed from what he's got, but that doesn't matter in this case)

http://audiozone.dk/cm/displayimage.php?pid=491&fullsize=1

It looks like that's what he's done, but note that nothing in that second diagram is grounded to the back of the volume pot. Everything goes to "System Ground".

[GuitariSteve]

Thank you dg!

Can you tell me the difference between shield ground and system ground?

[dg]

"Shield ground" refers to the bare wire that connects to the metallic shielding that surrounds the pickup wires. When you connect the bare wire to ground, interference is routed to ground and away from your pickup signal. In the case of the diagram for the Jackson pickup above, they may be assuming that the guitar also has cavity shielding, and recommend running the bare wire to it. You can do it that way if you have cavity shielding, or just wire it right along with your pickup ground wire.