LED switch wiring

[TLOPband]

Hello everyone. Was hoping I could get a bit of guidance for a mod I did on my PRS Mira.

 It was originally a two humbucker guitar but I put in a p90 in the middle position and changed the 3 way blade switch for a 5 way. I did a mod on my PRS Swamp Ash Special that uses an additional push pull pot on the volume (the tone is for coil splitting) to turn the bridge pickup on so I can have the neck and bridge together in position 1 (and all three pickups in position 2). For the Mira, I decided to put in a latching push button to do the same thing that also has an LED ring that lights up when the button is pushed in. Here's the link to the one I installed from Amazon:

Latching Push Button Switch, 16mm 12V Momentary Push Button LED Latching ON/Off Power Push Button Switch, 1 Pack Power Symbol+Ring LED Stainless Steel Waterproof (White) https://a.co/d/bBA5zVD

 

The issue I now have is that to power the LED I can use batteries, but the LED seems to constantly draw power from the button batteries I was using (2 × 2032s stacked in black electrical tape bundle with the positive and negative wires) so that even if I didn't have the LED on, the batteries go dead. I switched the button batteries for a square 9-volt (attached a 9-volt end onto the positive and negative wires) which worked fine but the battery got really hot. Then I tried two AAs with a battery box wired up and they got hot as well.

 So I'm not sure what to do about the LED light. It works well without it, but if I can't run it off of batteries then I should just go with a dpdt or something. Does anyone know if there are switches made for guitars that would run off of batteries that would do the job? I know I could certainly use a plain switch and hook up an LED wired to button batteries that I could make a hole in the pickguard for to show it's on, but if anyone knew of a switch designed for this that I could buy online then I would go with that. 

 Thanks for reading. And thanks in advance for any help

[curtisa]

5 hours ago, TLOPband said:

The issue I now have is that to power the LED I can use batteries, but the LED seems to constantly draw power from the button batteries I was using (2 × 2032s stacked in black electrical tape bundle with the positive and negative wires) so that even if I didn't have the LED on, the batteries go dead.

How exactly have you got the switch wired? If it's anything like the below switch I don't think this can be done without additional circuitry and components, or a different pushbutton;

The LED needs to be switched on and off using the contact in the switch, but you also need a dedicated contact for the pickup on/off function - they cannot be shared.

 

5 hours ago, TLOPband said:

the battery got really hot

Something's funky with the wiring. The battery getting hot suggests it's being shorted out when the switch/LED is in the off position. Post up some detailed shots of the wiring for the switch and battery.

[TLOPband]

35 minutes ago, curtisa said:

How exactly have you got the switch wired? If it's anything like the below switch I don't think this can be done without additional circuitry and components, or a different pushbutton;

The LED needs to be switched on and off using the contact in the switch, but you also need a dedicated contact for the pickup on/off function - they cannot be shared.

 

Something's funky with the wiring. The battery getting hot suggests it's being shorted out when the switch/LED is in the off position. Post up some detailed shots of the wiring for the switch and battery.

Ok I'll take it apart tomorrow and take some pics. I was running into an issue where the light would come on when the switch was turned on, but when the switch was off the light would just go dim and not off. In the end I did hook up the "spare" lug and that worked. I'll retrace the wiring tomorrow

[henrim]

If the battery gets hot there is definitely something wrong.

It looks to me that when the button is pressed current is flowing in to the pickups. That would explain the battery draining fast and getting hot.

[curtisa]

4 minutes ago, henrim said:

It looks to me that when the button is pressed current is flowing in to the pickups. That would explain the battery draining fast and getting hot

No, it'll be something else. Pickup DC resistance will be in the order of many K-ohms, which would result in insufficient current to cause battery heating. It's more likely to be a dead short.

The photos will probably show more clues.

[henrim]

56 minutes ago, curtisa said:

No, it'll be something else. Pickup DC resistance will be in the order of many K-ohms, which would result in insufficient current to cause battery heating. It's more likely to be a dead short.

The photos will probably show more clues.

Yes, my bad. Running current into coil doesn’t cause a short. I was trying to say that current is going somewhere where it shouldn’t through that switch. But I got the switch wrong. Now that I looked at the schematic you posted, it appears that the led is actually powered separately and thus current shouldn’t be leaking anywhere. So yes, there is a short elsewhere.

[TLOPband]

15 hours ago, henrim said:

Yes, my bad. Running current into coil doesn’t cause a short. I was trying to say that current is going somewhere where it shouldn’t through that switch. But I got the switch wrong. Now that I looked at the schematic you posted, it appears that the led is actually powered separately and thus current shouldn’t be leaking anywhere. So yes, there is a short elsewhere.

Ok I took the guitar apart and here's what the wiring looks like. The black wire joins LED negative, "Lug 3" and the battery's negative side. Red wires joins LED positive, "Lug 1", Lug 1 on the volume pot, and the positive side of the battery. "Lug 2" is attached to the bridge pickup. I tried lots of different combinations but this was the only way I came across that did what I wanted it to. Other ways either kept the LED dim when it was off and bright when on, or the LED wouldn't work at all.

 If you guys can see how to do it properly I'd love some help. 

 

[curtisa]

Yep - it will never work, sorry. The battery is dead-shorted in the off position, which is why it's getting hot and dying quickly. You're also sharing the LED circuit with the pickup. There's only one switching contact inside the pushbutton, and you really need two independent contacts - one for the LED and one for the pickup selection.

You could make the switch work but only if you dispense with the LED.

[TLOPband]

13 minutes ago, curtisa said:

Yep - it will never work, sorry. The battery is dead-shorted in the off position, which is why it's getting hot and dying quickly. You're also sharing the LED circuit with the pickup. There's only one switching contact inside the pushbutton, and you really need two independent contacts - one for the LED and one for the pickup selection.

You could make the switch work but only if you dispense with the LED.

Well that's too bad

 Thanks for all the help!

[curtisa]

You could install a little relay inside the control cavity to be driven from the switch. The contacts on the relay would then drive the LED and pickup selection separately and correctly. But it's a lot of fiddling around.

[TLOPband]

Just now, curtisa said:

You could install a little relay inside the control cavity to be driven from the switch. The contacts on the relay would then drive the LED and pickup selection separately and correctly. But it's a lot of fiddling around.

I wouldn't have half a clue how to do that lol

[TLOPband]

56 minutes ago, TLOPband said:

I wouldn't have half a clue how to do that lol

I did buy another type of switch, but would this work with the battery negative on one, the bridge wire and battery positive on the middle and a wire to the volume pot lug?

[curtisa]

No. You're still proposing sharing the circuits, which is half your problem.

[TLOPband]

6 minutes ago, curtisa said:

No. You're still proposing sharing the circuits, which is half your problem.

Understood. Thanks for your help!

[Bizman62]

As I understand very little about electrickery this has been an educative thread. Thanks for that, @TLOPband!

One question has popped into my mind during reading this:

Is there anything wrong without the LED?

I mean, the LED is obviously for the player to see if the mid pickup is "on", instead of a fancy lighting effect for the audience. A rocker switch with a self-luminous dot at the edge facing upwards might do the trick as well.

Something like this:

[TLOPband]

8 hours ago, Bizman62 said:

As I understand very little about electrickery this has been an educative thread. Thanks for that, @TLOPband!

One question has popped into my mind during reading this:

Is there anything wrong without the LED?

I mean, the LED is obviously for the player to see if the mid pickup is "on", instead of a fancy lighting effect for the audience. A rocker switch with a self-luminous dot at the edge facing upwards might do the trick as well.

Something like this:

It works fine without the LED, and I did suggest a three pin rocker switch with a small red LED in it in the reply I sent to Curtisa up there. I'll be switching to the rocker switch regardless and forego the light. It will be easier to tell if the rocker switch is on than the pushing switch by far

[henrim]

If you want to have a LED you can have a LED. It may be easier to go without but it doesn’t take much to have the LED if that’s what you want.

[TLOPband]

38 minutes ago, henrim said:

If you want to have a LED you can have a LED. It may be easier to go without but it doesn’t take much to have the LED if that’s what you want.

How would I make it work if I was to go with the 3 pin rocker switch I posted up above?

[curtisa]

2 hours ago, TLOPband said:

How would I make it work if I was to go with the 3 pin rocker switch I posted up above?

You can't. At least, not without adding extra circuitry that expands the number of switching contacts to your existing switch (hence my earlier suggestion of adding a relay) or using a different switch that already includes more contacts.

[curtisa]

Two alternatives.

1. Using an added relay to provide an extra set of contacts:

Advantages - makes use of the existing switch you've already installed.

Disadvantages - more bits to buy; as the battery dies you'll lose the ability to do the 'plus bridge' pickup selection.

Note: Relay and diode shown above can be bought from Amazon (eg here and here), but loads of other places sell them. 

 

2. Using a different switch:

Advantages - pickup selection will still work if the battery goes weak.

Disadvantages - this style of switch seems to be hard to come by and is a lot more expensive. May not be available in the same size as the one you already installed.

The switch shown is specifically this one. It's larger than the one you already bought so it would be wise to check it will still fit and will look OK if you're considering going this route. LED colour is red, but it's also available in blue, green, yellow and white.

 

[TLOPband]

58 minutes ago, curtisa said:

Two alternatives.

1. Using an added relay to provide an extra set of contacts:

Advantages - makes use of the existing switch you've already installed.

Disadvantages - more bits to buy; as the battery dies you'll lose the ability to do the 'plus bridge' pickup selection.

Note: Relay and diode shown above can be bought from Amazon (eg here and here), but loads of other places sell them. 

 

2. Using a different switch:

Advantages - pickup selection will still work if the battery goes weak.

Disadvantages - this style of switch seems to be hard to come by and is a lot more expensive. May not be available in the same size as the one you already installed.

The switch shown is specifically this one. It's larger than the one you already bought so it would be wise to check it will still fit and will look OK if you're considering going this route. LED colour is red, but it's also available in blue, green, yellow and white.

 

Wow this is awesome! I appreciate you going through all this trouble!