Gutted a guitar - bridge pickup not working

GordonBennett

I've been playing guitar on and off for 25 years. For the past few years I've just played an old classical guitar but I decided to get back into the electric and actually learn a few songs. I had an old 70s/80s Japanese Strat copy in the loft... completely uncared for and in a right state. I've never done any guitar work whatsoever but decided I'd like to replace everything on it for a bit of fun, and to learn about how it works and so on. Everything on it was working perfectly fine but the hardware was rusty and even the pickups were rusty.

So - I've gutted the whole thing, replaced the bridge, tuners, nut, output jack, pick guard, pots and pickups.

Once I'd completed the soldering I plugged in and tested the pickups and switch. To my absolute sheer amazement the neck pickup worked fine! And the middle pickup too! Fantastic - my heart soared. I flipped to the bridge pickup expecting it to be a formality and.... nothing... sigh... I knew it was too good to be true. There's a faint hum which increases in volume as I turn the volume pot up but that's all.

I should mention I haven't strung the guitar yet - I was just testing by tapping a screwdriver on the pickups.

Here's the wiring plan I followed:

https://ibb.co/pwFk391

The new wiring:
https://ibb.co/tXYpDNb

The old wiring (minus the capacitor which I nicked)
https://ibb.co/DWBS9BL

Sorry for the dogs dinner of the new wiring setup.

Also the new plan looks different to the original?

Well any help you can give would be greatly appreciated. I've read about wiring the pickup straight to the output jack to test whether its working - good idea? The guy I purchased the pickups from said it's like one of the pots?

Any help is greatly appreciated.  

SteveRobinson

It's quite possible that the pickup has failed, especially if it was rusty. Do you have a multimeter to test the resistance?

GordonBennett

SteveRobinson said:

It's quite possible that the pickup has failed, especially if it was rusty. Do you have a multimeter to test the resistance?

I'm going to get hold of a multimeter to do some testing. The old rusty pickups were working, but in any case I've replaced them with brand new pickups - and it's the brand new bridge pickup which isn't working.

maltingsaudio

GordonBennett said:

SteveRobinson said:

It's quite possible that the pickup has failed, especially if it was rusty. Do you have a multimeter to test the resistance?

I'm going to get hold of a multimeter to do some testing. The old rusty pickups were working, but in any case I've replaced them with brand new pickups - and it's the brand new bridge pickup which isn't working.

Not unusual for new pickups to fail so test with a multimeter, however I would also have a close look at the solder on the pickup selector. The red and white lead in the picture look to me very close at the solder point so if there is a stray hair there that could be your problem

ICBM

It's nothing to do with the pots if the other pickups work - I'm sure you'll have realised that already .

It could well be the switch - that type are cheap and unreliable. The simplest way to test this is swap the bridge and one of the other pickup connections on the switch and see which position now doesn't work - if the bridge end position is still dead it's the switch. If the fault moves with the pickup it's the pickup.

Once you've identified and hopefully fixed the problem, it's well worth undoing the pickup wiring again, shortening the wires to the correct length and neatly twisting the pairs - it's not only tidy, it drastically reduces noise.

It's not just you, the Fender Custom Shop can't get this right! I fixed this one... before and after:





Just doing that reduced the noise by more than half.

GordonBennett

maltingsaudio said:

Not unusual for new pickups to fail so test with a multimeter, however I would also have a close look at the solder on the pickup selector. The red and white lead in the picture look to me very close at the solder point so if there is a stray hair there that could be your problem

Thanks, I'll take a closer look at that and give it a test.

GordonBennett

ICBM said:

It's nothing to do with the pots if the other pickups work - I'm sure you'll have realised that already .

It could well be the switch - that type are cheap and unreliable. The simplest way to test this is swap the bridge and one of the other pickup connections on the switch and see which position now doesn't work - if the bridge end position is still dead it's the switch. If the fault moves with the pickup it's the pickup.

Once you've identified and hopefully fixed the problem, it's well worth undoing the pickup wiring again, shortening the wires to the correct length and neatly twisting the pairs - it's not only tidy, it drastically reduces noise.

It's not just you, the Fender Custom Shop can't get this right! I fixed this one... before and after:

Just doing that reduced the noise by more than half.

Thanks - I'll test that. What switch would you recommend?

Great tip on the wiring and twisting the pairs - I'll do that and trim it all down. thanks for the pics - very useful. Seems I'm in good company (or bad?) with Fender!

ICBM

GordonBennett said:

What switch would you recommend?

CRL if you don't mind spending that much! Oak Grigsby a little cheaper, but marginally less reliable in my experience. Below that it's all a bit of a gamble...

Check it's the switch first though, not a great deal of point in replacing it if it's actually working.

Funkfingers

GordonBennett said:

… old 70s/80s Japanese Strat copy …

The old wiring (minus the capacitor which I nicked)

https://ibb.co/DWBS9BL

Your original pickguard assembly wiring includes three entirely redundant red wires between the two poles of the selector switch.

The connections between pickups and tone pots is achieved via the blue jumper wire between the two “collector” terminals of the selector switch.

I recognise those old pickups with the metal base plates. I had a pair of them in a plywood Lead II copy. They are atrocious and, hence, ideal for slide. 

ICBM

Funkfingers said:

Your original pickguard assembly wiring includes three entirely redundant red wires between the two poles of the selector switch.

They're not redundant - they make the switch far more reliable. Although, this only works properly if you have two separate tone caps, or the neck and middle pickups are on together when both tone controls are turned down.

You should always wire any spare poles of a switch to parallel the switching - it increases reliability for no penalty other than a little time. (And can reduce switching noise sometimes.)

Devil#20

Just a couple of observations from me. What composition is your solder and/or what power is your soldering iron? The solder doesn't look like it got hot enough because it hasn't flowed. Don't rely on the flux core in the solder. Use some additional flux and just give the solder points a tickle with a bit of wet and dry before you tin them. Where you are bridging the c-c and 2-3 terminals on the switch it makes it easier to use a bit of unwound guitar string instead of short bits of wire. Lay it across the terminals, solder it on and then snip it flush. You aren't fighting for space then.  

GordonBennett

Devil#20 said:

Just a couple of observations from me. What composition is your solder and/or what power is your soldering iron? The solder doesn't look like it got hot enough because it hasn't flowed. Don't rely on the flux core in the solder. Use some additional flux and just give the solder points a tickle with a bit of wet and dry before you tin them. Where you are bridging the c-c and 2-3 terminals on the switch it makes it easier to use a bit of unwound guitar string instead of short bits of wire. Lay it across the terminals, solder it on and then snip it flush. You aren't fighting for space then.  

That's great advice re the bridging - thanks for that. The iron is a 48 watt and goes up to 500 degrees c apparently... So I just turned it up to max. I must admit it didn't always melt the solder as I would have liked. Re the solder itself, no idea... It came with the soldering iron. Guess I need to buy some flux then?

Devil#20

GordonBennett said:

That's great advice re the bridging - thanks for that. The iron is a 48 watt and goes up to 500 degrees c apparently... So I just turned it up to max. I must admit it didn't always melt the solder as I would have liked. Re the solder itself, no idea... It came with the soldering iron. Guess I need to buy some flux then?

That's probably the problem then. The solder that comes with the soldering iron in a kit is usually totally shit and there's not enough flux in it which promptly boils off. Get some with lead content if you're in the UK and open the window. I still recommend using some additional flux rather than rely on the core flux. Tin the iron tip and wet and dry the connection area. I like Weller irons and tips. Oh and another tip. Either wash your hands before you start or wear nitrile gloves. If you twist the wires together the grease from your fingers will compromise the joint.   

GordonBennett

Thanks everyone for their help. I took a break on this but got back to it, desoldered everything and removed the pickup. I tested it with a multi meter and there was no resistance. Faulty pick up after all...! I've now got a new, working, pickup and am now ready to start the job again and resolder everything from scratch following the advice on here.