Buttercaster Pickup Problem

Hey kids, some of you may have seen the "Buttercaster" thread over on the main page.

I'm having a pickup issue.

Bridge pup seems to be working normally while the tone knob is way up. When I turn the tone down, the volume drops off, going completely dead when the tone is rolled all of the way off.

Pots seems to check out okay. 0-238 ohms.

Tone control controls the neck pup as it should.

When I wire the bridge pup to the output jack it sounds jus like it should.

The bridge pickup has two ground wires...I am running both of them to ground on the volume pot.

I must have something shorting out somewhere...but I haven't been able to track it down.

Haven't replaced the tone pot...after all it IS working with the neck pup.

Anybody have an idea on what I should try or look for?

Steve...can you take a close up picture of your wiring? Should be a simple fix... Sounds like your shorting your bridge pickup to ground with the tone pot somehow. Are you sure you have the tone cap hooked up right?....Does the tone control work correctly when you have selector selecting both pickups? If so...when you switch to the bridge only ...the switch must be doing something funky wiring wise...

Even our heros have feet of clay...

; )

Steve...can you take a close up picture of your wiring? Should be a simple fix... Sounds like your shorting your bridge pickup to ground with the tone pot somehow. Are you sure you have the tone cap hooked up right?....Does the tone control work correctly when you have selector selecting both pickups? If so...when you switch to the bridge only ...the switch must be doing something funky wiring wise...

Brian...tone works fine on neck pickup only. In middle position, it sounds like when it is full off, there is no bridge pup - as with the tone rolled completely off, positions 2 and 3 sound identical. In position 1, all I have is neck, until I roll the tone back, then it goes away.

FWIW, I originally had a 4-way switch in there...and it BEHAVED THE SAME WAY. Then I put a Stew-Mac 3 way in...same deal...now it is doing this with this "Fender" 3-way. If it is the switch, I am doing something VERY consistently. ;-)

Here are some pix...

http://www.backwaterpartymusic.com/%20buttercaster/switchend600.jpg

http://www.backwaterpartymusic.com/%20buttercaster/switch600.jpg

http://www.backwaterpartymusic.com/%20buttercaster/toneend600.jpg

http://www.backwaterpartymusic.com/%20buttercaster/volumecenter600.jpg

Even though it looks like the center lug on the tone pot might be touching the unused one, it isn't.

I'm still baffled...with my feet stuck FIRMLY in the MUD.

I can't see anything in those pictures that would cause that. I recommend disconnecting the tone cap from the wiper of the tone pot and see what happens then. You may need to undo a few things to break the problem down to the area that is bad.

The volume going to zero with the tone turned down sounds like a shorted tone cap, but then you say it works OK on the other PU. Strange. Are you sure you didn't inhale too much nitro? :shock:

...Strange. Are you sure you didn't inhale too much nitro? :shock:

Not with my new high $$$ Darth Vader Model respirator.

I think a few days ago I did disconnect that tone cap...didn't notice anything different...but I'll try it again tonight and take better notes.

When I find it, it will be one of those "slap the forehead" moments.

Is there anything in the pickup itself that could be causing this? Three wires - 2 from the coil and 1 from what I assume is the baseplate/ground. I did disconnect the baseplate ground from the ground on the back of the volume pot...and that didn't change anything except increase the hum when I'm not touching the strings. Could a couple of those be touching somewhere that would produce these symptoms? Doesn't seem so to me...but then...if I knew what I was doing...this would be working. :wink:

Thanks for the suggestions guys...

Steve..I'll study the pics and think some more... In the meantime maybe it's that ORANGE capacitor.. If you use the GREEN ones it might sound/work better :mrgreen: :shock: :mrgreen:

...The volume going to zero with the tone turned down sounds like a shorted tone cap, but then you say it works OK on the other PU....
When I put a meter on that cap, it indicates that it is an open, or broken path. Infinite resistance. (and yes, that was with the cap removed from the circut. :wink:) If it was shorted out, it would be zero. Eh?

Does it behave the same way whether the control plate is bolted down or unattached, as in these pics? It is hard to tell, just from the pics, whether there could be any accidental shorts that come into play when the control plate is bolted in place. I see the bypass cap has dangling legs, which could come in contact with something. The tone cap also has a lot of its legs exposed, which could lead to a short, if things got compressed when the control plate is bolted in place. (I've encounted quite a few problems like this. They disappear when the control plate is removed.)

Does it behave the same way whether the control plate is bolted down or unattached, as in these pics? It is hard to tell, just from the pics, whether there could be any accidental shorts that come into play when the control plate is bolted in place. I see the bypass cap has dangling legs, which could come in contact with something. The tone cap also has a lot of its legs exposed, which could lead to a short, if things got compressed when the control plate is bolted in place. (I've encounted quite a few problems like this. They disappear when the control plate is removed.)

Are you hinting that I should buy Terry's "How to Wire and Solder" video?

:wink:

I KNOW it is not the bypass cap...because it was doing it before I put it on. But...it could WELL be some other sort of general sloppiness. I will check it out tonight.

But...I am not optimistic about that...as last night I took EVERYTHING off the control plate, unsoldered EVERYTHING...and put it back together...only to have the same problem show up. If it is something like you suggested...I am tremendously talented in being able to reproduce it. :wink:

Keep 'em coming kids!

Cheers

Steve Dikkers
aka Buckocaster 51

Might I suggest wiring the bridge pickup directly to where the switch would normally connect to the volume pot?

This will determine whether the problem is with the switch and it's wiring or not. If the problem still exists, further troubleshooting will be that much easier.

My $0.02

...Might I suggest wiring the bridge pickup directly to where the switch would normally connect to the volume pot?...

Just gave that a try.

Guess what?

Tone pot STILL does the same thing.

So we have elimanated the switch.

Next we'll try Terry's suggestion of removing the tone cap from the circuit.

Stay tuned.

:roll:

Without the tone cap...surprise...the guitar turns into a One Trick Pony. Volume works. No tone control.

Does that mean I have a bad cap?

Replaced the 0.047 mf with a 0.033 mf becuase that is all that I had.

Still the same thing!

grrr...

I'm going to swap out the pot next...

Different 250 meg pot.

Still the same thing.

I'm beginning to think there might be something going on with the pickup.

I am perplexed.

So...I measured the resistance of the NECK pickup...about 5600 ohms on my super deluxe meter.

The BRIDGE pickup...the one with three wires...reads OPEN between any and all combinations of the three wires.

I'm thinking that I might try a different pickup.

Remove that second ground wire from the pickup............ you've got nothing to lose at this point.

Better yet, replace the pickup like you're thinking.

That's right...nothing to lose...and GUESS WHAT?

A different pickup seems to WORK!

What I don't understand is why the first one even worked at all...

I am TOTALLY baffled.

Thanks for all of the help guys.

Buckocaster,
is that the pickup that surprised you with the 3 wires when you first looked at it? I remember having a pickup mightily cornfuse me when it had 3 wires rather than two and I had almost the same experience... it was a few years ago, I can't remember what i did....

So...I measured the resistance of the NECK pickup...about 5600 ohms on my super deluxe meter.

The BRIDGE pickup...the one with three wires...reads OPEN between any and all combinations of the three wires.

I'm thinking that I might try a different pickup.

What kind of pickup is it that it has 3 wires?

I'm pretty ignorant about these things, but I can't help thinking that third wire might be something other than a second ground. What if you hooked one up to ground and just capped the other one off?

I'm pretty ignorant about these things, but I can't help thinking that third wire might be something other than a second ground. What if you hooked one up to ground and just capped the other one off?

Thank makes two of use that don't quite understand these things.

I did try it with:

both to ground
black to ground and blue capped
blue to ground and black capped

behaved the same way

There has to be something going on inside of it.

Fortunately, like most of us, I had an "extra" bridge pickup laying around. But now since I used my "spare," I'll have to start looking for another.

:wink:

By the way, what kind of pickup is that that was causing you the problem?

I'm glad you fixed it. It would be interesting where the magnet wire in the pickup broke. It would have had to be inside the windings somewhere. In that case , it makes sense there would have been enough inter-winding capacitance to get sound out of it with the wire broke. I bet it didn't have much low end. Rolling in the tone cap would shunt it all to ground. Usually the break is near the outside, and you get no output. I have never seen one do what yours did.

The 3 wire interface allows you to ground the bridge plate, but isolate the winding from ground in case you wanted to wire it in series with another pickup. I believe it is more common to see this done in neck pickups.

...I bet it didn't have much low end...

You ain't just a-whistlin' Dixie. I noticed that...but it is a Tele bridge pickup after all...I guess I just figured that is the way this one was supposed to sound.

And...

the onliest way I could balance the neck pickup with it was to crank that neck pup ALL THE WAY down. The bridge pickup didn't have much volume.

The symptoms were all there...I just didn't know how to read them...this time.