1990 Clapton Sig Strat -No Output

[tclotworthy]

Hi. I have a 30+ year old Clapton strat. While playing today, the output signal suddenly disappeared. I assumed battery, but replaced with brand new and still no output. By the way, the chord and amp are fine. It’s definitely the guitar.

I have wiggled jack, fiddled with knobs and 5 way switch, still nothing except occasionally pops. I know all the pots are dirty because I never do any maintenance and they are always noisy when adjusting.

Can someone give me some guidance on good home diagnostics to diagnose and hopefully fix? I am pretty handy. I am just trying to avoid waiting weeks or months for a shop repair. Pointing in the right direction or making specific recommendations would be greatly appreciated! Thanks!

 

[Mekhem]

It might be the output jack. I had to have that re-soldered on my 96.

Not sure how to home test that though

 

[Cali Dude]

I had something like that happen once years ago on mine. It turned out to be the Lace Sensor pickup had died in the bridge. I had to replace the pickup.

 

[24 track]

maybe check there the battery connects to the preamp some times a contact will fall off , and the battery cable is the most jostled wire inside.
easy fix but a pita !

 

[tclotworthy]

As an update, I am certain it is not the jack. When I turn up the volume knob, the hum gets louder (so signal definitely going to that pot). Same with the mid-boost pot (hum goes up). Nothing with the middle pot. So I am guessing something with the signal downstream from pots? Switching between the settings on 5-way has not effect at all on hum or output (e.g., no pickup has output). Not sure whether this helps narrow down or inspires additional ideas. I appreciate the replies!

 

[1stpitch]

Have you pulled the pickguard off and checked the battery wires as @24 track suggested? Also, there are other wires running to the preamp board, 6, IIRC. Could be a broken solder joint, or a cold solder joint showing up. Check every connection in there. Look up a Clapton Strat wiring diagram.

 

[ahiddentableau]

First thing I'd do is pop the hood, grab a meter and check that the battery power is reaching the circuit. It could be something has gone wrong with the mid boost circuit and so you've got no output for that reason.

If you've got power, I'd trace the circuit with a tracer to make sure the board is working right.

If that's working, then I'd trace from the pickups/switch to the boost board (to make sure the pickup signal is getting there in the first place), and from the output of the boost/preamp board to the output jack (to make sure the output is getting to the jack).

I suppose it's possible that the problem is with the pickups or switch but I'd guess the boost board and output jack are considerably more likely. So I'd start with those.

Good luck!

 

[tclotworthy]

Great feedback, thank you everyone.

I need to learn how to signal trace this guitar. I am pretty handly and figure i can do it with some guidance/instruction. Plus, I need to buy a circuit tracer I guess.

1) Is there some basic guidance available on how to perform a signal trace on this guitar (or similar guitar)?
2) What is a relatively inexpensive circuit tracer that would be adequate for my needs?

 

[Boreas]

Great feedback, thank you everyone.

I need to learn how to signal trace this guitar. I am pretty handly and figure i can do it with some guidance/instruction. Plus, I need to buy a circuit tracer I guess.

1) Is there some basic guidance available on how to perform a signal trace on this guitar (or similar guitar)?
2) What is a relatively inexpensive circuit tracer that would be adequate for my needs?

I use a cheap automotive continuity tester - preferably one with a beeper as well as a light. Usage is pretty intuitive.

I would start by working all of your controls, including the switch, vigorously for 20 cycles or so. That is usually enough to clean contacts enough to troubleshoot.

 

[dsutton24]

Rather than bashing around in a haphazard fashion, I'd try to be a little bit methodical about things. I would take an old guitar cable, cut off one plug, and attach alligator clips to the ground and signal carrying wire.

Turn off the neck pickup, attach your clips to the neck pickup, and make sure it works. Check the other two pickups likewise. Figure out where the output from the switch is and check there, and so on to the output jack.

 

[tclotworthy]

@dsutton24 I like your idea, but I am not following your instructions. You say "take an old guitar cable, cut off one plug, and attach alligator clips to the ground and signal carrying wire." I understand cutting off one end of the cable. You don't say what to do with the cut off end of the cable, and its not clear what I do with the alligator clips. I would need sometime like "attach one clip end to blah, and the other to blah", and "attach one cable wire to blah and another to blah". If its too much trouble, thanks anyway,

 

[Tuxedo Poly]

Good advice above.
I would look at the switch and check the lug with the yellow wire is making contact in sequence with the other 3 lugs soldered to the pickup hot wires.
This Clapton diagram may help. It is afaik for the early model there were upgrades in 2001 and onwards. The battery connector may have red and black wires with the black joined to the yellow wire going to the output jack

 

[schmee]

Hi. I have a 30+ year old Clapton strat. While playing today, the output signal suddenly disappeared. I assumed battery, but replaced with brand new and still no output. By the way, the chord and amp are fine. It’s definitely the guitar.

I have wiggled jack, fiddled with knobs and 5 way switch, still nothing except occasionally pops. I know all the pots are dirty because I never do any maintenance and they are always noisy when adjusting.

Can someone give me some guidance on good home diagnostics to diagnose and hopefully fix? I am pretty handy. I am just trying to avoid waiting weeks or months for a shop repair. Pointing in the right direction or making specific recommendations would be greatly appreciated! Thanks!

OK, I have used these systems extensively.
-I will say, the little colored wires that go into the board are stiff and they break loose at the board (or other places) readily. Not sure why Fender doesn't use more flexy wire. First thing I would do is open it up and look around for loose or broken joints.

-Next is the special output jack. I have found that if it is not rotated proper orientation, the lugs may bend against the body wood and cause wire breaks or shorts. One lug of the jack powers the battery to the PCB when a cord is plugged in (so the battery doesnt go dead when not in use) If this is jammed maybe it's not powered? Has the jack been loose lately?
Loosen the cup that holds the jack and let it hang to try playing the guitar.... does that fix it?

 

[1stpitch]

@tclotworthy, after seeing your responses to some of the suggestions, and knowing what it takes to work with these circuits, I would suggest you take this to a guitar tech.

 

[dsutton24]

@dsutton24 I like your idea, but I am not following your instructions. You say "take an old guitar cable, cut off one plug, and attach alligator clips to the ground and signal carrying wire." I understand cutting off one end of the cable. You don't say what to do with the cut off end of the cable, and its not clear what I do with the alligator clips. I would need sometime like "attach one clip end to blah, and the other to blah", and "attach one cable wire to blah and another to blah". If its too much trouble, thanks anyway,

I really don't mean to be rude, but if you're 'pretty handy' you shouldn't need to be led by the hand. Those are nice guitars, it's probably time to take it to a technician.

 

[Milspec]

Is this Strat sporting the Lace Sensor pickups? They use a very thin magnet like the old computer floppy discs and can be very fragile. I am actually surprised they didn't all die off after 10 years. I have a '96 with them and they haven't died yet, but I have heard stories.

Was this event a sudden response or was there any odd noise / sound issues leading up to the dead stick result? If it was sudden, you have a wire issue. Either the jack failed or a main ground might have failed. Once opened up, you should be able to spot it just by visual inspection.

Good luck

 

[xtrajerry]

I use a cheap automotive continuity tester - preferably one with a beeper as well as a light. Usage is pretty intuitive.

I would start by working all of your controls, including the switch, vigorously for 20 cycles or so. That is usually enough to clean contacts enough to troubleshoot.

This ^^^

 

[xtrajerry]

Rather than bashing around in a haphazard fashion, I'd try to be a little bit methodical about things. I would take an old guitar cable, cut off one plug, and attach alligator clips to the ground and signal carrying wire.

Turn off the neck pickup, attach your clips to the neck pickup, and make sure it works. Check the other two pickups likewise. Figure out where the output from the switch is and check there, and so on to the output jack.

Not even necessary to cut the cord just clip the jumper to the center and ground or get a 1/4” plug and clip to the terminals. Even though I have a couple dozen or more cords of various lengths most still unused I couldn’t bring myself to cut one.

 

[tclotworthy]

I really don't mean to be rude, but if you're 'pretty handy' you shouldn't need to be led by the hand. Those are nice guitars, it's probably time to take it to a technician.

 

[tclotworthy]

"I really don't mean to be rude" hey, no point in being condescending. Just ignore all my posts in the future and we'll get along great