LP Wiring

[Milty]

Hi Guys,
So today I wired up my LP according to the diagram on the PBG site.
Plugged it in and;
With the switch in the neck (up) position it the volume and tone are working
with the switch in the middle, the neck volume and tone pots are working, the bridge volume pot works though it seems not through the full range (it cuts out with the volume between 1-3 and 8 -10 or there abouts)
With the switch in the neck (down) position i have nothing.
As far as i can see all wiring is in the correct position.
The grounding wire to the back of the pots doesnt follow the exact path shown on the diagram though it does cove all bases in a loop.
If anybody has any ideas id be very appeciative.
Thanks in advance
Milty

[Rossc0]

Hi Milty. I had something similar. In my case the shielding on the wire from 3 way switch to one of the pots was earthing so no signal. So a good starting place would be to ensure you have no rogue earths.

[WeirdBits]

Photos of the wiring and cavity, as close and clear as possible, can help a lot with diagnosing problems. Often we can see something that may not be evident from a description.

[Milty]

Thanks guys
Ill post some photos asap.
I forgot to mention i have applied copper shielding tape to the pot cavity and switch cavity

[Simon Barden]

A stray whisker of copper signal wire to the shielding is often the culprit in these cases, though it is possible that there's a faulty pot or switch. Look at all the connections and check that you can't see any strands of wire sticking out. If you can, cut them right back to the solder. If not, then as said, photos will help.

[Milty]

the pot on the far left with the blue wires is the volume pot for the bridge PU.
The brown wire is the grounding wire.
Ive had a look and I cant see any where the wires are touching any where they shouldnt be.
Appreciate any advice guys

[Simon Barden]

A few comments.

1. The ground solder connections on the back of the pots are poor. They look all hard and blobby. For a good solder connection, the solder should have flowed across some of the pot and look smooth over the wire. It looks like you aren't getting the back of the pot hot enough. These solder joints really need to be redone.

2. From what I can see, the ground wire from the jack loops out over the neck tone pot (can't see if there's a break in the insulation and it's soldered to the back of the pot but I'm assuming not) then hits the back of the bridge tone pot, then runs to the bridge vol pot. Looks like three ground wires on the back of the neck vol pot, but I can only see where two of them go (unless one is the bridge grounding wire). So unless the jack ground goes first to the neck tone pot, there is no obvious ground link to the neck volume and tone pots except via the copper shielding. I'd add a ground link between the two tone pots.

3. The 'live' side of the tone capacitor legs look to be able to easily touch the tone pot casing. With the tone control right up, this allows the pickup signal to be shorted straight to ground. I'd re-do those connections and either get hold of some heat-shrink sleeving or two small length of stripped wire insulation and slip them over the 'live' legs of the capacitors (the ones from the pot tag) so they can't short out.


It may be easier to de-solder all the wires and start again. You'll need a solder sucker or soldering braid to remove the old solder from the back of the pots and the pot tags (never re-use old solder). I'd also rub the back of the pots down with some sandpaper, say 400 grit but a bit coarser or finer will do, and if you've got any naphtha (lighter fluid) or cleaning alcohol, then rub the back of the pots with that to help de-grease them. Melt some solder on the back of the pots first (so you get a nice flat shiny pool of solder that's sticking to the pot), and also tin the ends of the ground wires.

A helping hand is useful when you solder the ground wires on to the pots as you need to keep the wire pressed against the pot whilst pressing the soldering iron against the pot and the wire at the same time whilst adding solder to the join. The solder should make a nice smooth shiny joint, and not clump up as it has in your photo.

Once you get the back of the pot hot enough, it should all just fall into place. But once you get to that point, remove the iron as you don't want to overheat the pot, and continue to hold the wire in place until the solder hardens. ideally the wire should be touching the back of the pot with a smooth hill of solder on top and around the sides. You don't want the wire raised above the surface of the pot and held up by a blob of solder.

[Milty]

Thanks Simon,
appreciate you taking the time to review and comment.
Ill take your advice and have a go at starting over.
One question i have is how hot is too hot with the back of the pots?
I was worried that if i held the iron on theback of the pot for too long i may damage the pot.

[Simon Barden]

You can overheat them, (I've done it myself) but you've also got to get it warm enough to melt the solder. It is a bit Catch 22. If you can get the pots out of the body to solder, then you should be able to use some metal grips to clamp on the sides of the pot to act as a heat sink and helps stop the heat travelling down to the pot's track.

Speed is the key, but if you've already got solder spread on the back of the pot, then getting the new solder to stick to the solder on the pot is quicker than getting new solder to stick to the back of the pot directly. It's the pot equivalent of tinning the wire first. And roughing up the surface to remove any oxidised metal helps as well.

And having an extra pair of hands does speed things up as you don't get the wire suddenly pulling off the back of the pot so you've got to do it all over again.

[ricklt]

The pot top right position in your pic there is a wire that looks like it runs from the back of the pot in between the pot and body of the guitar. Am I right or am I seeing things that aren't there?

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