One for the wiring gurus

[Hardcoretroubadour]

I have no idea when it comes to wiring. I am attempting to wire up a neck and bridge bullbuckers with split coils and push pull pots. With a treble bleed. I copied this format from my ex4 bass where it works fine. To me it all looks ok, neck pickup (grey wire) seems to make noise but bridge does not. I have no idea how to use a multimeter, but I did acquire one from my mother-in-law who used to build all sorts of things. Have I wired something wrong, or how do I use the multi Metre to test if humbucker is working properly.

[Marcel]

Great old meters those ones... Had one for years until some idiot dropped it off a ladder....

In your situation you really only need to use on the main dial the green X10K range. Once set get the two leads and press them together and the pointer on the meter should deflect to the other side of the dial. It should point to zero ohms, and if it doesn't then use the top right knob to adjust it so that it does point to zero ohms. The meter has now been "zero'd" and the readings off the meter can be read with reasonable accuracy and consistency. If you change to the X1K range then you will need to re zero the meter to maintain accuracy in your readings.

Using the probes you can now measure the resistance between any two points. If there is a direct path the meter will read zero. If there is a PU coil or a pot in the path then the meter will consistently read some value that is not zero. It helps if yo set the pots to about the 1/3 or 2/3 of the range of travel as this will help you differentiate between earth wires and pots ant PU's. The two PU's may not read the same value, and typically the bridge PU will often deflect the meter less than the neck PU due its higher DC resistance. If it is an open circuit or there is nil DC path between the two probed points then the meter will remain "at rest" as it is in the photo.

Look at the diagram, look at what you have wired. compare the two. Pick two points and test.... With that meter you cannot damage anything by testing continuity between any two points, so test away anywhere and everywhere and compare to what the diagram says you should have.... The error will eventually make itself known to you..

Good luck..

BTW... nice heat shrink work...

[Simon Barden]

Heat shrink can unfortunately hide dry joints, so check that the wires all make good solder connections to the pot tags etc. When i was doing the SG, one of the tone pot wires was poking through the hole in a pot tag, but the heatshrink was also just poking through the hole and stopping a connection. Was a matter of seconds* to correct this and get everything working.


*Anything is just a matter of seconds, but in this case it was about 60, rather than 100,000.

[PJSprog]

What Simon said. Check and re-heat all of your solder joints. Cold solder happens easily, and is easy to miss.

[Hardcoretroubadour]

Thanks Marcel, Simon and sprog. Just so i am clear on some things, do I need to remove the heat shrink enough to get to 'bare wire to test, or can this be done by pushing the pointed probe into the join? Is the reading then effected when I have multiple wires going to one tab?
Am I correct to assume that I should start with the bridge pickup wire and have the black probe on the ground wire and red on the yellow hot wire. From what I have read this should be about 8000 parsecs or so (or some equally incomprehensible unit of measure)

[Marcel]

What you are measuring is resistance quantified in ohms.

All you need is metal to metal contact on both probes... the electrons will sort themselves out no matter how small the contact points are. Removal of heat shrink is only needed if you cannot make a decent metal to metal contact with your probes, or your measurements don't add up hence where the advice from Simon and Sprog makes sense. If the measurement you make makes sense to you then there is no need to remove the heat shrink. Pushing the probe through the heat shrink is a last resort, try for other places first or try to get to exposed metal at the ends of the heat shrink.

If there are two or more wires to a particular measurement point then you will likely have "resistance in parallel" Google search the term for an explanation.

8000 ohm is a reasonable value for a moderate humbucker. 12000 ohms is not unusual for a 'hot' humbucker. A Tele single coils can be as low as 5000 ohms. Seriously Hot humbuckers can be as high as 16000 ohms or more.

Two 16000 ohm (16k) humbuckers wired in parallel will measure as 8000 ohms (8k). A 8000 ohm bridge humbucker and a 7000 ohm (7k ohm) neck humbucker wired in parallel will measure close to 3750 ohms (3.75k ohm). Pots in humbucker guitars are usually 500000 ohm (500k) types and often can be hidden to meters by their high resistance value when compared to PU's.

If you measure across the output jack and the meter see's/measures 500k then the the wiring is not letting the PU be seen by the jack but the meter does electronicaly see the volume pot.... It IS simple logic like that... Measure across the output jack, volume set to max (10) and in our example above you get 7000 ohms, then yes the neck PU is the only one connected to the output socket....
And a telling one is the meter is measuring across the output socket and it shows zero ohms, which most often means that the selected PU is shorted to your shielding somewhere inside your build.

[DrNomis_44]

Check out my mini-tutorial on how to use a multimeter, here's a link to it:

https://www.buildyourownguitar.com.a...ead.php?t=5608


Here's another link to a mini-tutorial that you might find useful:

https://www.buildyourownguitar.com.a...ead.php?t=5604


Here's another one:

https://www.buildyourownguitar.com.a...ead.php?t=5653

And one more:

https://www.buildyourownguitar.com.a...ead.php?t=5604

[Hardcoretroubadour]

Cheers guys, I'll have a look in a few days when I finish laying the turf in the yard

[Simon Barden]

A classic procrastination technique!

[wazkelly]

Cheers guys, I'll have a look in a few days when I finish laying the turf in the yard

Hey buddy, should be same as your Bass if you did a split setup on it.

I would start with running multi meter across all wires on the bridge HB to see which ones give a reading in relation to each other to identify any faults or broken connections within the pickup.

Part of the problem could be the instructions that may or may not have come with pickups as from one brand to another the wires can often be different colours which adds to the confusion. For a standard HB pickup they usually arrive with a pair joined (red & white is quite common) with a black and green (plus shield) flying solo or shield and ground also paired off. The multi meter should help with identifying which wires belong to which coils and then you can figure out which ones go where on the push/pull switch. This is where it can also get tricky as some switch diagrams show a few different ways to go, either split or possibly parallel. Been a while since I last did this so memory is a bit faded but it could be there somewhere in my EX1 build diary however I was installing Toneriders but that shouldn't matter. It was a similar scenario when doing Entwistle HB splits in my son's Strat, just different coloured wires.

Not my favourite part of a build either but best attacked with a clear head and many spare hours with minimal external distractions.

Hope this helps in some way.

Cheers, Waz