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Stratocaster - technical questions for dead guitar
Old 7th August 2020
  #1
Stratocaster - technical questions for dead guitar

Hi all,

sorry for the huge post - here's a tech question regarding my stratocaster. I bought this guitar used a long while ago. Beautiful sound and feel. When the thing failed, I took it to the shop. According to them, two of my pickups are dead (shorted out). They did mention that one of them was still working (neck or bridge, can't remember).

Question 1: anyone know these pickups? Do they really just break for no good reason?





The shop left me with desoldered pickups. I can solder, but I don't understand electronics. In the image, you can see the 'stellar' soldering job that was done by whoever fitted the instrument with the active SD pickups.





I wanted to know which pickup is good and started by desoldering everything and cleaning up as much as possible. You can see the crazy amount of solder I took out.



Next, I soldered everything back together again, however, the wiring scheme I used was different from what was used before. Before, every leg of the 5-way switch and the pots were used. I referred to a wiring scheme from the Seymour Duncan web site which is shown below. One leg of the capacitor broke off, but my understanding is that this only affects the sound somehow and is not a vital part for testing.

The guitar makes no sound whatsoever. I was hoping to hear at least one pickup (and secretly hoped all of them came back to life ).

Question 2: Does the connection scheme look right?





As you can see in the video clip, all pickups have about the same reading on the multi meter. All readings with cable plugged in and taken from the other end of the cable (that would go into the amp). If the pickups were indeed shorted out, I would exoect infinity or through (beep), but nothing in between.

Question 3: What does this reading tell me? Is it possible that dead pickups give out such a reading and is there anything else I can test for?



If you're still reading, thank you very much. I will likely have to replace everything under the pick guard, but perhaps I'll learn a bit while I'm at it. Thanks for any input on this!

Stefan
Old 7th August 2020
  #2
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uOpt's Avatar
I recommend that you do not try to wire up the entire pickguard.

One by one, connect a single pickup to nothing but the batteries and a hot wire (plus ground of course). Crocodile clips can come in handy. Then tap the pickup with a screwdriver while hot is connected to an amp to see whether the pickup works.

I think these are Seymour Duncan Lifewires pickups, but I don't know the older actives that well. You might want to ask on forums.seymourduncan.com. They'll set you right up.

P.S. no way these pickups "short out". As you say, chances are that they are allright.
Old 7th August 2020
  #3
Quote:
Originally Posted by uOpt View Post
I recommend that you do not try to wire up the entire pickguard.

One by one, connect a single pickup to nothing but the batteries and a hot wire (plus ground of course). Crocodile clips can come in handy. Then tap the pickup with a screwdriver while hot is connected to an amp to see whether the pickup works.

I think these are Seymour Duncan Lifewires pickups, but I don't know the older actives that well. You might want to ask on forums.seymourduncan.com. They'll set you right up.

P.S. no way these pickups "short out". As you say, chances are that they are allright.
Thanks uOpt, good points here. I guess I'll desolder again and follow your advice testing one at a time. I'll also post at the seymourduncan forum to hopefully find out what the reading is supposed to say.
Old 7th August 2020
  #4
Quote:
Originally Posted by uOpt View Post
One by one, connect a single pickup to nothing but the batteries and a hot wire (plus ground of course). Crocodile clips can come in handy. Then tap the pickup with a screwdriver while hot is connected to an amp to see whether the pickup works.
Interesting - now I do not get a reading at all. Am I doing this right? I plugged the instrument jack in to engage the batteries and connected the pickup lead(s) to one pin of the meter and the ground to the other pin. 5-way switch and pots are not part of this setup.

Replacing the meter with the actual output cables also does not make a sound when tapping the pups with a screwdriver.

Old 7th August 2020
  #5
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uOpt's Avatar
You can't do ohm meter readings on active pickups. You don't have access to the coils, just the output of the opamp.

If all three are still not making a sound when isolated on the batteries you probably have a screwup like reversed batteries?

These pickups are hard to kill and unlikely to be dead.
Old 7th August 2020
  #6
One more thing I just noticed: I took fresh batteries and when testing the output into the amp, they got quite hot and the output voltage dropped more than 1V within a minute or so. Now that's pretty bad, I'd say.
Old 7th August 2020
  #7
Quote:
Originally Posted by uOpt View Post
You can't do ohm meter readings on active pickups. You don't have access to the coils, just the output of the opamp.
I see, didn't know that. That explains the readings on the assembled pickguard which was probably the pots then.

Hopefully the opamps didn't give up, although I don't see how this could possibly happen with all three at the same time.

Is it ok to test like I did with all pickups connected to the batteries at the same time? The grounds are also still connected, only the leads are separated right now.

I'm worried about the hot batteries, though...
Old 7th August 2020
  #8
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Rick Dalton's Avatar
Quote:
Originally Posted by stefangs View Post
Interesting - now I do not get a reading at all. Am I doing this right? I plugged the instrument jack in to engage the batteries and connected the pickup lead(s) to one pin of the meter and the ground to the other pin. 5-way switch and pots are not part of this setup.

Replacing the meter with the actual output cables also does not make a sound when tapping the pups with a screwdriver.

Example of what has happened. Take a piece of 41 to 44 AWG/ pickup winding, then short it cross a 9 volt battery, you have to be fast, if you want to light a cigarette though. The wire will vaporize, so you can figure the pickup winding's have an open if you're not getting a reading, just as blowing an fuse.
Old 7th August 2020
  #9
Quote:
Originally Posted by Rick Dalton View Post
Example of what has happened. Take a piece of 41 to 44 AWG/ pickup winding, then short it cross a 9 volt battery, you have to be fast, if you want to light a cigarette though. The wire will vaporize, so you can figure the pickup winding's have an open if you're not getting a reading, just as blowing an fuse.
Yes, but as pointed out above, I wouldn't be holding the battery to the ends of the coil, but to the output of the op amp. I suppose to be sure, you'd have to disassemble the pickups, but that isn't meant to happen - they are sealed.
Old 7th August 2020
  #10
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Rick Dalton's Avatar
Quote:
Originally Posted by stefangs View Post
Yes, but as pointed out above, I wouldn't be holding the battery to the ends of the coil, but to the output of the op amp. I suppose to be sure, you'd have to disassemble the pickups, but that isn't meant to happen - they are sealed.
Is that a rubber or epoxy filling? You may be able to access the PCB. I've done it on EIM's for vehicles. Might try and put a sharp edge on a screwdriver, make it into a chisel and heat it up.
Old 7th August 2020
  #11
I suppose I could do that, but I know almost nothing about electronics, so I figure that at best I would find nothing, at worst I'd do more damage
Old 7th August 2020
  #12
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uOpt's Avatar
An ohm reading across the power input of the pickups would be interesting.

Looks like one might have a shortcut in the power circuit?

Okay, but all three?
Old 7th August 2020
  #13
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Rick Dalton's Avatar
Quote:
Originally Posted by stefangs View Post
I suppose I could do that, but I know almost nothing about electronics, so I figure that at best I would find nothing, at worst I'd do more damage
Can you try just one pickup? And get the complete wire up in the picture, also with just one battery. the two 9 volts, 18 volt is for more overhead, just one will supply these pickups for testing. And have you done a continuity test from shield to the white/output wire, with pickup only? and same with shield and the hot/red wire.
Old 7th August 2020
  #14
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Rick Dalton's Avatar
Quote:
Originally Posted by stefangs View Post
connected the pickup lead(s) to one pin of the meter and the ground to the other pin.


OK, But you don't mention connecting the battery ground to the pickup ground, and unless I'm missing something? I cant see battery ground to pickup shield/ground in any of the pictures so far.
Old 7th August 2020
  #15
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Mikhael's Avatar
 

Active pickups are still coils and magnets, just weaker than passives. If the preamp is NOT in the pickups, you can still test the coils' resistance. If the preamp is IN the pickups, my first thought would be to get rid of the silly buggers and get some decent passives. But that's mainly because I'm not a fan of actives.

If you can get these ID'd (and you probably can, by someone at SD or their fan forum), then you can get some diagrams of which wire goes where and does what. Then you have info to work from.

Oh, and if something's getting hot, and battery voltage droops quickly, you've got a short somewhere. If it's wired up, unhook the battery and take a resistance reading across the terminals that the battery plugs into. That'll tell you if the battery's seeing a short somewhere in the circuit.
Old 7th August 2020
  #16
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Rick Dalton's Avatar
Quote:
Originally Posted by stefangs View Post
Interesting - now I do not get a reading at all.
Do you know how to do a diode test with your meter? If so, test the red wire with the ground, then do the same with the white and ground/shield. Then the red and white. after that, reverse the leads of the meter and read again. jot all reading down. But first, can you confirm that you do have battery ground going to pickup ground?
Old 7th August 2020
  #17
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mbvoxx's Avatar
I'm guessing those pickups are the SS1 set. But you can buy an entire loaded pickguard with new vol/tone/tone pots, switch,and pickups ready to drop in and just solder the +/- leads to the output jack...for not much more than the price of a good set of pickups, with your choice of pups and pots, and pg color. Plus you can opt for some cool mods with the Vol/tone/tone pots and get a blender pot on one of the tone pots. worth consideration and the install is a lot easier.

If it were my Srat that's exactly what I'd do.
Old 7th August 2020
  #18
Quote:
Originally Posted by stefangs View Post
One more thing I just noticed: I took fresh batteries and when testing the output into the amp, they got quite hot and the output voltage dropped more than 1V within a minute or so. Now that's pretty bad, I'd say.
At least one pickup has a dead short. Unfixable, since they're potted.

You need to talk to Zoobiedood, he's our local Duncan guy.
Old 7th August 2020
  #19
Quote:
Originally Posted by uOpt View Post
An ohm reading across the power input of the pickups would be interesting.

Looks like one might have a shortcut in the power circuit?

Quote:
Originally Posted by Mikhael View Post
Oh, and if something's getting hot, and battery voltage droops quickly, you've got a short somewhere. If it's wired up, unhook the battery and take a resistance reading across the terminals that the battery plugs into. That'll tell you if the battery's seeing a short somewhere in the circuit.
Here's my test setup: I've already soldered all the ground and hot wires together with shrink tubing, and I suppose I sadly will have to take that apart again to be sure. Indeed there's a zero reading right now. I can set the meter to beep mode and it beeps. If the setup is as I think it is, then there's a problem right there. Hope you can make it out in the photo.

Old 7th August 2020
  #20
Quote:
Originally Posted by Rick Dalton View Post
OK, But you don't mention connecting the battery ground to the pickup ground, and unless I'm missing something? I cant see battery ground to pickup shield/ground in any of the pictures so far.
When I didn't get a sound, I disconnected and just connected to the meter instead. That's in the photo. I didn't take a picture when I had the actual signal lead connected.
Old 7th August 2020
  #21
Quote:
Originally Posted by Mikhael View Post
If you can get these ID'd (and you probably can, by someone at SD or their fan forum), then you can get some diagrams of which wire goes where and does what. Then you have info to work from.
Quote:
Originally Posted by Rick Dalton View Post
Can you try just one pickup? And get the complete wire up in the picture, also with just one battery. the two 9 volts, 18 volt is for more overhead, just one will supply these pickups for testing. And have you done a continuity test from shield to the white/output wire, with pickup only? and same with shield and the hot/red wire.
I cross posted this over at the Seymour Duncan forum and someone responded right away with "a set of the original Livewire 18v strat pickups". So they actually need 2 batteries for voltage, not longer life - crazy!

And yes, the preamps are built into the pickups.
Old 7th August 2020
  #22
Quote:
Originally Posted by Mikhael View Post
If the preamp is IN the pickups, my first thought would be to get rid of the silly buggers and get some decent passives. But that's mainly because I'm not a fan of actives.
Hehe, I hear you. I would have never picked actives ones myself, since I loathe changing batteries and making sure I don't forget unplugging my guitar all the time. That said, I bought the guitar used like that and truth be told, they sound fabulous. If I end up replacing them, and it looks like I will need to, then I will go for a nice set of passive noiseless, but that's what my other thread here is for.
Old 7th August 2020
  #23
Looks like I found the culprit. The middle pickup has a short between power and ground. Neck and Bridge pickups do not. So next I will only connect those two and see if I get audio.

Edit: here it is:



Guys, you are awesome - thank you so much for your help with this - it's greatly appreciated! Now if I could only fix the middle one

Last edited by stefangs; 7th August 2020 at 11:04 PM.. Reason: added video
Old 7th August 2020
  #24
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Rick Dalton's Avatar
Quote:
Originally Posted by stefangs View Post
Here's my test setup: I've already soldered all the ground and hot wires together with shrink tubing, and I suppose I sadly will have to take that apart again to be sure. Indeed there's a zero reading right now. I can set the meter to beep mode and it beeps. If the setup is as I think it is, then there's a problem right there. Hope you can make it out in the photo.

You still have all three, ganged and not doing a diode test, you have a setting on the meter for that, look up how to do it. the way you have all ganged, with one being bad can make them all show shorted/bad.
Old 7th August 2020
  #25
Quote:
Originally Posted by Rick Dalton View Post
You still have all three, ganged and not doing a diode test, you have a setting on the meter for that, look up how to do it. the way you have all ganged, with one being bad can make them all show shorted/bad.
Yup, I just changed that. Only the middle pickup is bad, the other ones are fine. See video above I just added to the previous post. I'm happy to have found the culprit and sad at the same time for not being able to fix it all. But this was a very educational day for me :-)
Old 7th August 2020
  #26
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Rick Dalton's Avatar
Take each one, wire it to battery by itself, set your meter to AC voltage, put the red lead to white wire of pickup, and black lead to ground ,tap pickup with screwdriver, etc.. see if you get a reading. Do each one like this. EDIT: Also check your battery lead with the meter, to see you have voltage, set it on DC voltage.
Old 7th August 2020
  #27
Quote:
Originally Posted by Rick Dalton View Post
Take each one, wire it to battery by itself, set your meter to AC voltage, put the red lead to white wire of pickup, and black lead to ground ,tap pickup with screwdriver, etc.. see if you get a reading. Do each one like this. EDIT: Also check your battery lead with the meter, to see you have voltage, set it on DC voltage.
Did that - bridge and neck work when tapped. But the middle one does not - it has a short between the power lead and ground.
Old 7th August 2020
  #28
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Rick Dalton's Avatar
Quote:
Originally Posted by stefangs View Post
Did that - bridge and neck work when tapped. But the middle one does not - it has a short between the power lead and ground.
you just do, or you had already, before I mentioned it?
Old 7th August 2020
  #29
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Rick Dalton's Avatar
Quote:
Originally Posted by Rick Dalton View Post
you just did, or you had already, before I mentioned it?
OK,Sorry I see now, these post kind of lag. Well youve two, do they put out?
Old 8th August 2020
  #30
Quote:
Originally Posted by stefangs View Post
I cross posted this over at the Seymour Duncan forum and someone responded right away with "a set of the original Livewire 18v strat pickups". So they actually need 2 batteries for voltage, not longer life - crazy!

And yes, the preamps are built into the pickups.
Not crazy at all. Commonplace for higher output systems.
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