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Post by frets on Jul 21, 2022 12:23:45 GMT -5
Hi Guys,
Seems like I only come here when I have problems. I’m wiring this old Yamaha Pacifica for a friend. I put a nice harness in it. Check out everything. Do the tap test. All pickups work. Put the strings on and yep, you guessed it, no sound. In all my years of doing this I have never had this happen, or had anybody teach me about this happening. They are cheap pickups but it’s like they have gone into some weird microphonic dead zone. It’s simple wiring so I know it’s right. Has anyone had this problem? Pickups work but not one iota of sound when the strings are in place? As always, thanks.
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Post by unreg on Jul 21, 2022 14:30:50 GMT -5
During my klon clone pedal build, I learned that new stereo input/output jacks are tough to plug a cable into. After testing the internals with multimeter, and being instructed to switch two positive wires on the 9V power jack, one time, my pedal did not make any sound. I tried inserting the input cable while the pedal was uncovered and instantly noticed that the cable going into the pedal’s stereo input jack had not been fully inserted. I need to use more force to insert that input cable. After the input cable is fully inserted, the pedal works! Why this would affect the guitar you’re working on, I don’t know. Just thought this has a small possibility of helping.  |
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Post by b4nj0 on Jul 22, 2022 3:04:37 GMT -5
Since you have to wire a Leo-type with the pickguard off the guitar, did you tap test the pups on the bench and now it's in the guitar you have this manifest C? As a quick first step, do you think it's worth trying disconnecting the bridge ground wire? I suspect you have a short to "ground" somewhere and the process of assembly is introducing it.
Edit: I had this happen once with the simplest of single PUP wiring when I changed a hummer to a P90. The cause turned out to be that the guitar's manufacturer had used an amp type input socket for the guitar's output and the third contact was hidden behind timber in the snug rout, I had wired to the switching tab on the socket shorting the output to deck. That had me beat for ages because I visually assumed that the "simple" socket wiring had to be correct. Another gotcha was screening my 1973 USA Fender Strat and the tip of the plug was touching the football rout screening. That had me foxed for a while too.
でつ e&oe ...
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Post by newey on Jul 22, 2022 6:42:25 GMT -5
Another gotcha was screening my 1973 USA Fender Strat and the tip of the plug was touching the football rout screening. That had me foxed for a while too. I've had that happen, and I don't shield the football rout anymore. It's unlikely that the two wires to the jack would contribute to any noise, but if one is worried about it, better to use a shielded cable to the jack. But Yamaha Pacificas, IIRC, don't have the regular football-type jackplate but use a side jack like an LP. It can't be the string ground, it isn't carrying signal and is supposed to be grounded anyway. I agree with b4nj0, if it bench-tested OK but didn't work after assembly, then screwing down the pickguard shorted something to somewhere it shouldn't be touching. SInce all pickups are affected, it must be between the pots and the jack. frets, When you say "no sound", are we talking dead quiet? Or is there some noise? The "down 'n dirty" fix for this type of problem is a layer of electrical tape in the control cavity, both underneath and on the underside of the pickguard (assuming the cavity has been shielded). But I'd try to find the short first. |
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Post by frets on Jul 22, 2022 11:37:22 GMT -5
Newey,
On the bench, the pickguard is fully affixed to the guitar. Jack is in the guitar. I plug it in and the tap test works fine. Put a string on it and it’s dead quiet. Pop the pickup with the screwdriver and you get a nice clear sound. The cavity and pickguard are shielded so I can’t figure where a short would be coming from given the tap test works with the pickguard fully in. The jack cavity is not shielded. I typically don’t shield end jacks due to shorting potential. It’s very strange. You can tap the pickup and get a full noise but when I even scrape the string on the pickup, nothing. I don’t see how it could have a short given the pickups work on the tap test. But at this point, I’m willing to try anything.
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Post by sumgai on Jul 22, 2022 11:46:28 GMT -5
Some years ago, I had a customer with the same symptoms, dead on arrival. He had done the wiring himself, and swore that he had bench tested it before re-assembly. I double-checked, right in front of him, by plugging in a cable, and putting the meter leads across the other end of said cable. Yeppers, a big fat 0 ohms. This was a Strat clone, so with the strings still on, I unscrewed the 'tail' area, lifted it up slightly, and Lo & Behold, sound galore. A close peek inwards revealed that the Vol pot was rotated so that the lugs were facing the side wall of the fully shielded cavity. Guess what that caused..... He said that he had cut a wire too short, and made up for that by rotating the pot. I told him to go home and put a longer wire in it, and to twist the pot back where the lugs belonged, facing the other controls. Didn't charge him. He became a friend, and sent a fair amount of business my way. Moral of the story: Our good friend Mr. Murphy has paid you a visit, leaving behind a short between the hot lead and ground when you put the pickguard in place and screw it down. newey's "down and dirty" fix is a good one, and acceptable to most folks, but he's also correct: find and fix it properly, so that the next person to look under the hood doesn't go "awww geez, Mickey Mouse has been in here". HTH sumgai p.s. No, it's not always problems that brings you back time and again.  You've kept up a pretty steady stream of contributions in the Tone Control sector, and no little amount of overall wiring schemes. We'd be more than a bit poorer for the lack of you, trust me on that one.  |
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Post by frets on Jul 22, 2022 14:34:48 GMT -5
Thanks Sumgai,
(And Newey)
I will do the dirty fix with fleece harness tape. Sticks better. What gets me though is when the pickguard is fully screwed down, the tap test works. A signal is getting out. But it must be a short.
I’ll let you guys know after I gussy it up😺.
Thanks again!
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Post by newey on Jul 22, 2022 20:10:48 GMT -5
You're not using some kind of wacky strings with no steel in them??  |
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Post by frets on Jul 22, 2022 20:42:08 GMT -5
Newey,
No, I’m using Slinky’s.
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Post by ashcatlt on Jul 23, 2022 0:21:17 GMT -5
You're not using some kind of wacky strings with no steel in them?? Lol yeah nylon strings don’t work. But I got nothin on this one. Really weird. Wish you luck! Let us know if you figure it out. |
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Post by b4nj0 on Jul 23, 2022 4:16:43 GMT -5
newey: Sure the bridge ground doesn't carry any signal, but it could be shorting to someplace that does, especially if it wanders around a bit to allow a little slack for manoeuvre. Am I the only one who crimps on a ring terminal and attaches the string ground under one of the spring "claw" attachment screws? So much easier than trying to solder to the claw. frets: sumgai is correct about your contributions, the much missed karma points were made for folks like you C. でつ e&oe ...
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Post by newey on Jul 23, 2022 7:14:04 GMT -5
Sure the bridge ground doesn't carry any signal, but it could be shorting to someplace that does True enough. And I have used a ring terminal as you describe. frets- I too am stumped on this one. Maybe some photos of the guts would point up a problem but I'm fresh out of suggestions. |
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Post by frets on Jul 23, 2022 11:31:08 GMT -5
I will post pics after I take it apart and fleece tape the cavity and appropriate portion of the pickguard. Thanks you guys for trying to help me on this.
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Post by Deleted on Jul 24, 2022 2:38:06 GMT -5
Just thinking here as it doesn't sound like a short.
It sounds like the sensitivity of the pickup/circuit, so that it can sense big metal but not small amounts.
Been trying to Google Metal detectors for any passive reason how to drop the sensitivity
Could there be a fused part within the pickup coils that reduces the magnetic Field, just enough to slap but too far for the strings .. just trying to think of strange things (not including acts of God(s) or Aliens or even Q)
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Post by frets on Jul 24, 2022 14:35:23 GMT -5
Angellahash😸,
I appreciate it. Thank you!
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Post by frets on Jul 24, 2022 15:05:24 GMT -5
Don’t think this is going to help anyone to figure this out. I could simplify the wiring. It’s not one of my best jobs. The switches are a 4PDT Series/Parallel and a DPDT Neck On. Push Pull Volume/Coil Split Concentric Tone Artec VTB active pot Like I said, I don’t expect anyone to see anything in this. Except my battery placement😺   |
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Post by Yogi B on Jul 25, 2022 2:57:49 GMT -5
Like I said, I don’t expect anyone to see anything in this. Except my battery placement😺 Or just the fact you even have a battery. Just to be sure, your previous tests yielded the same result both when the VTB/VTC was enabled and when it was bypassed? Also related to the battery, shouldn't the negative lead have a separate connection to the output jack (assuming that you're switching power via a stereo/switched jack socket). Both wires from the battery snap disappear into the mass of wires, with no obvious continuation. I do see the second orange wire disappearing behind the pickguard, but as far as I can tell the other end is grounded so I'm assuming it's the string/bridge/trem-claw ground — maybe it's that instead? Since you're getting the "thuds" of the tap test, but not the sound of the strings that would make me think it could be frequency dependent — maybe not a direct short but one through a large capacitor, therefore perhaps one of the VTB/VTC's coupling caps? Though those should disconnected when it's bypassed (and it's much less likely that you're simultaneously inadvertently shorting to both hot & ground), plus that wouldn't really explain why you got no output when touching the strings against the pickups. Do you have a tuning fork (or similar, I guess you could hold the pickguard up to the strings of another guitar) in order to test the wiring, via some method other than tapping, whilst it's outside the cavity?
Additionally, is that a grub screw (or maybe the end sheared off of a previously too long height adjustment screw) magnetised to the underside of the bridge pickup? Might it have a friend lodged somewhere in your wiring? |
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Post by frets on Jul 25, 2022 12:10:43 GMT -5
Yogi, I have not tried it with the VTB disconnected from the wiring. I didn’t think it made a difference if I ran the battery’s negative to the back of a pot. Does it have to be on the stereo jack? If so, that’s an easy fix. Yes, I did clip the pickup screws and “yes” one could be within the wiring somewhere. Looks like a rewire for me. It was a mess anyway. Here is the draft diagram of it I whipped together. I was wondering if I had a problem in my wiring.  |
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Post by frets on Jul 25, 2022 12:14:34 GMT -5
Yogi,
I do not have a tuning fork but I see your point. When I do rewire I am try with and without the VTB. And I will use the stereo jack because I forgot that turns the darn thing on and off😺.
Thank you for your help. I appreciate it.
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Post by unreg on Jul 25, 2022 15:45:41 GMT -5
(Obviously, I have nothing to helpful to add here.) Wow! frets has 7 Green stars now! You are truly an important helpful cog in this forum… thank you so much! |
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Post by frets on Jul 25, 2022 16:31:29 GMT -5
It was the VTB pot. I don’t know if the coupling capacitor is bad but it got pulled. I’ll find something passive to put in that spot.
I should have known it was most likely the VTB. I’ve just never had one fail on me. Thanks to you all for helping me figure this out.
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Post by unreg on Jul 25, 2022 17:16:35 GMT -5
I didn’t think it made a difference if I ran the battery’s negative to the back of a pot. I know you’ve figured this out, but for other readers: Soldering battery negative to the back of a pot always allows that battery circuit to be complete; so, the battery is always used. Using a stereo jack allows battery negative to be soldered to the jack’s ring; thus, no cable inserted means the battery circuit can’t be completed; so, the battery isn’t used when a cable isn’t inserted bc the stereo jack’s ring doesn’t connect to anything (ground). EDIT: A mono (TS) cable plugged into a stereo (TRS) jack enables the battery circuit to be complete bc that cable’s sleeve connects to the stereo jack’s ring. The cable’s sleeve, when the other end of that mono cable is inserted into an amp, is connected to amp’s ground; thus, the battery circuit is complete. FINAL EDIT: If the battery’s negative terminal is connected to the back of a pot, that means the battery’s negative is probably connected to the entire guitar’s ground circuit… and that is enough area/material to act as a ground read Yogi B’s correction below, so the battery is used even if the guitar isn’t plugged in. |
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Post by Yogi B on Jul 26, 2022 0:56:32 GMT -5
Looks like a rewire for me. It was a mess anyway. Here is the draft diagram of it I whipped together. I was wondering if I had a problem in my wiring. Though you've now found the source of the problem, there's still a couple of things that leap out at me from that diagram. Firstly it appears you've shorted the 'upper' half of the volume pot (i.e. the side that wouldn't kill the signal, but would make the control pretty unresponsive). Starting at the left lug (3) you have a lime green wire going to your concentric tone control, which is then connected via the red jumper to the pink wire and in turn is connected to the middle lug (2) of the volume control. (My guess is that you don't want the pink wire.) Secondly that series/parallel switch is a Dirk Wacker creation (which should be enough to instil at least caution, if not other things) it does do as described, toggling positions 2 & 4 to series — however that comes with the caveat that in series mode positions 1, 3 & 5 are left open, with no output. (Though this is admitted in the original article, greater emphasis probably should have been used on this point.) To be honest, whilst keeping the series combinations at the same positions as their parallel equivalents is a neat trick I'm not sure it's worth the cost of a 4PDT and three dead spots — especially considering that you can get 1-B×M, 2-M, 3-M, 4-M, 5-M×N with only a SPDT (i.e. taking this Phostenix diagram and replacing the blend pot with a switch). FINAL EDIT: If the battery’s negative terminal is connected to the back of a pot, that means the battery’s negative is probably connected to the entire guitar’s ground circuit… and that is enough area/material to act as a ground, so the battery is used even if the guitar isn’t plugged in. Area/material has very little to do with it, only whether or not there is a completed circuit. Whilst you would technically loose a tiny amount of charge due to capacitance (which usually does increase with area), this would be a one off cost — once the capacitor was charged no more current would be drawn from the battery. The only way this could become a recurring cost is if the capacitor were to be discharged and this could only happen by completing a circuit in parallel with it, but that by necessity means you'd also be completing a circuit for the battery. It is not that the ground wiring is large enough to "act as ground", but the fact that the positive terminal is connected to it (obviously not directly, but via the circuitry), thus by also connecting the negative terminal to it you'd have a compete circuit. |
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You've kept up a pretty steady stream of contributions in the Tone Control sector, and no little amount of overall wiring schemes. We'd be more than a bit poorer for the lack of you, trust me on that one. 
