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Post by dustyboy316 on May 25, 2008 22:33:12 GMT -5
Hey guys. I got my guitar back from a shop a long time ago and only the rhythm pick up worked. I have a 3 pick up les paul, so I think it's a bit busier in the cavity. Anyways first of all I want to know if anyone knows how I can fix it, as I can't really seem to pick up the error in schematics (I'm not the best with them, but I understand them). Also if we get that fixed I want to know how to get rid of the middle pick up out of the circuitry. I don't have a use for it and am getting 2 new EMG's to replace the old pick ups. Anyways I can provide pictures if need be. There is a schematic on this site: www.axiomatic-music.co.uk/acatalog/CircuitDiagrams.html . AnywaysI can't find anything wrong personally, so I don't know if anyone has an ideas on the top of their heads, if not I'll just take it into the shop when my EMG's come in.... but I want some wiring experience if I can.
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Post by newey on May 26, 2008 7:31:15 GMT -5
Dusty- Hello and Welcome! What was it in the shop to have done? Was your tech supposed to be messing about with the wiring? And, if it worked properly when you took it in and didn't when you got it back, did you not take it back into the shop demanding an explanation? It need be. As I understand it, your diagnostic questions here are really just for learning purposes, since ultimately you are replacing both lead and rhythm pickups anyway, with the middle dewired, and just looking pretty, filling the hole in the middle of your guitar? As opposed to ideas extracted from one's nether region? ;D Well, OK: 1) It is extremely unlikely that 2 pickups would suffer internal failure simultaneously. Therefore, the problem is a wiring problem and the wiring to the pickup selector switch is the likely culprit. 2) If your tech was inside the guitar for some reason, then there are any number of possibilities as to what he/she did. If the trip to the shop was for setup, intonation or whatever, then the likelihood is that a wire or wires simply rattled loose from from the switch. 3) The diagram you link to is simply a standard wiring scheme for an LP. It uses a different switch than the one you have on your 3 pickup version. You could rewire your existing switch to eliminate the middle pickup, but it would probably be easier to just get a standard LP toggle switch and rewire it according to the diagram in your link. (Or have the shop do so when you get your EMGs installed). 4) You should utilize ChrisK's "Brain scan through a nostril" diagnostic technique found here and post your results. You will need a multimeter to do so, but any seriuos guitar troubleshooting requires the use of one anyway. You can post photos, and someone may spot something thereon, but it's hit or miss. 5) I'll ignore the question of why you so dislike your middle pickup, to each his or her own, as they say. Are these the active variety of EMGs you are getting?
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Post by D2o on May 26, 2008 10:03:04 GMT -5
Hey, Dusty! Welcome to GN2. When I first came to GN2, it was a wiring issue that brought me, and I was not that comfortable with wiring, soldering and all that. But, bottom line, short of taking it to a tech, you've got to dive in if you want to fix it. That's what I did, and have been doing ever since. If you've got a bit of spare time so that you're not rushing things, it's a lot of fun. Here's a link to Gibson's wiring schematic for the only 3 pickup Les Paul that I saw there. www.gibson.com/Files/schematics/lpafwiring.gifIf I were you, I would take the control cavity covers off and see how your wiring stacks up against the schematic. You can always just put the covers back on if you decide you don't want to perform surgery. On the other hand, since you want two pickups and you're getting EMGs put in at the shop anyway, what have you got to lose in (carefully) farting around with trying to get it up and running? And you might gain a bit of wiirng experience. As for taking out the other pickup, I suppose you would just forget that it ever was a three pickup Les Paul, and wire it according to a 2 pickup Les Paul schematic, like the one you have provided or this (I find Seymour Duncan schematics easier to look at than Gibson schematics) www.seymourduncan.com/pdfs/support/schematics/2h_2v_2t_3w.pdf , but you should have a look at the colour coding to make sure you've got the right wires going where they should be. Your post doesn't state whether your current setup has both a 3 way switch AND a 5 way rotary switch. If it does, I think you would just ignore the 5 way and wire it using the 3 way. I hope that helps.
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Post by wolf on May 26, 2008 13:41:42 GMT -5
DD842 Yes, Gibson schematics are rather boring. However, one "advantage" they have over the Seymour Duncan schematics is that they don't have 4 wires coming out of the pickups. Except for someone replacing the factory pickups, when was the last time (if ever) Gibson issued a guitar that had all 4 wires coming out of the pickups?
As anyone here knows, I absolutely hate, despise, loathe, condemn, etc those 2 wire chrome covered epoxy filled bricks that Gibson likes to use so much. Still, the Gibson schematic is the one to follow if you want to rewire the guitar to the way it was manufactured.
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Post by D2o on May 26, 2008 14:17:07 GMT -5
DD842Yes, Gibson schematics are rather boring. However, one "advantage" they have over the Seymour Duncan schematics is that they don't have 4 wires coming out of the pickups. Except for someone replacing the factory pickups, when was the last time (if ever) Gibson issued a guitar that had all 4 wires coming out of the pickups? ..... ..... the Gibson schematic is the one to follow if you want to rewire the guitar to the way it was manufactured. So, like, that's important? That slipped my mind as I was thrown off by Gibson 4 wire pickups like the Gibson 490R and T and the 498T. However, note their note (factory installed pickups have two conductor wiring). You're right! Thanks! ----------------------------------------------------------------------------------- Modern Classics 490r & 490t These "Modern Classic" pickups feature tonal characteristics similar to the '57 Classic, but deliver a slight increase in the upper mids, for a more contemporary humbucking sound. The special Alnico II magnet gives these beauties a singing quality that delivers on demand. The 490R, with its neck-spaced pole pieces, is calibrated to match the bridge-spaced 490T for a perfect match. Available with chrome, gold or nickel covers, or with open coils, the 490R and 490T come with four conductor shielded wiring for series/parallel/split coil variations. NOTE: Factory-installed 490R and 490T pickups have two conductor wiring.498t "hot alnico" Put a slightly hotter Alnico V magnet into a specially wound coil combination, and you get the 498T "Hot Alnico." With its higher output and emphasis on mid-ranges and highs, the 498T is the perfect rock pickup. Available with chrome, gold or nickel covers, or open coils, the 498T comes with four conductor shielded wiring for series/parallel/split coil variations. NOTE: Factory-installed 498T pickups have two conductor wiring.
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Post by dustyboy316 on May 26, 2008 15:54:05 GMT -5
Thanks so far guys, I'll get pics soon.
I'm taking it in to replace the pick ups when they arrive so I'm just going to see if I can do it more than anything.
Yes they are active EMG's, I have an 81 coming. I also have a Seymour Duncan Screaming Demon coming too. Pretty sure I'm going to put the 81 in, but then I have to get it wired differently. Emg sent me a schematic to mix a passive and an active pick up in a Les Paul, so I'll bring that in when I go.
When I brought it into the shop I just got a jackplate on it basically. It was desoldered too (I stepped on the input jack when standing up and completely ripped it off). It took awhile too, I'm hesistant to bring it back, and my friends dad owns it...
That schematic is going to help for sure. Thanks so far, I'll post later tonigt when I'm not so busy.
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Post by dustyboy316 on May 26, 2008 16:30:01 GMT -5
Ok, here's some pics: I've pointed out where I think the problem is. It looks like those 2 wires are crossed. How it would happen I don't know. Also only one wire comes from the pick ups, but it crosses over so other ones, so I don't think this is a problem. It actually goes to the working pick up, so maybe one of the pick ups wires are stuck in the guitar somewhere?
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Post by dustyboy316 on May 26, 2008 16:47:15 GMT -5
Ok, I rewired the wire from the pick ups to the other potentiometer and nothing happened. It still worked on the rhythm channel but not on the treble...
Oh and DD 842 I have been diving in. I tried some minor surgery on it before but to no avail. I want to get a little more serious help though because I'm basically out of ideas.
Oh and that diagnostics test is for a Strat, I didn't read it all but could I apply it here too?
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Post by newey on May 26, 2008 17:22:03 GMT -5
DB- A clue! The plot thickens! The toggle switch in a Gibson is "last in the chain" before the output (not "input") jack. So, when you ripped the jack wiring loose, it's likely that you pulled on the wiring to the toggle switch as well. Or perhaps the shop yanked it while rewiring the jack. Either way, they must not have tested the thing before returning it to you. Post some pix of your toggle switch, I'll bet that's where the problem lies. Also, the wiring diagram you have posted is for an "Ace Freley" Model, you haven't said if that's what you have or not, but if not, it may be a different wiring scheme than yours. Absolutely, the logic of the testing is the same, you are basically testing all positions of the selector switch sequentially.
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Post by wolf on May 26, 2008 17:53:16 GMT -5
Here's a graphic of a typical Les Paul guitar wiring from my website www.1728.com/guitar.htmDo you need to know what an SPDT (single pole double throw) center on switch is? Then go here: www.1728.com/project2.htm(Yeah, that's another page from my website ;D) In an actual Les Paul, you may have noticed that the pickup switch is about a foot away from the volume and tone controls but the circuit is still the same. If you don't have a test meter do you have alligator "jumper" clips? With these you could really see if your bridge pickup is working but be prepared to cut it totally out of the circuit. Heck, this is Guitar Nuts and we do things like that quite often.
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Post by dustyboy316 on May 26, 2008 18:00:27 GMT -5
Yup it's basically the exact same as the Ace Frehley. They actually told me it was the exact same except for the name when they game it back to me. I'll get some pics of the switch soon and post.
I know I have a multimeter around somewhere, where do u want me to test?
I'll be back soon to post pics, too busy now.
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Post by dustyboy316 on May 26, 2008 22:08:27 GMT -5
Here are some pics of the switch. It's really blurry so I can explain whats going on if needed. It's hard to check that schematic for the switch wiring, I'm a little lost. In this pic it is the 3 sided part of the switch. A red wire is connected to the first position from the bottom left potentiometer on the first prong, which looks ok to me. The middle prong red wire goes to the top of the top right potentiometer for the rhythm pick up. The far one comes from the pick up and is split into 2 prongs (one being on the other side of switch) which also looks good to me. On this side on the first prong a white wire is connected to the output jack as well as soldered to the wires which go to the middle lowe prong. The middle prong is extremely busy, all together it looks like it has a wire from the output jack, a wire which connects to the bottom left potentiometer top, a wire from the middle pick up and it looks like thats it. The far right prong is connected to the same spot as in the middle one which connects to the top of the bottom left potentiometer. Oh and I think I figured it out, there is no wire soldered into the middle prong of the bottom left pot. The wire that is supposed to be there , which is connected to the middle prong on the first picutre, is connected to the top of the top right pot. If I desolder it and attach it to the bottom left pot should this solve my problems? Also the diagram has to rotated 90 degress clock wise, it's easier for me to explain that way, so it matches up exactly with my guitar. I'm actually going to go try this and see what happens.
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Post by dustyboy316 on May 26, 2008 22:22:45 GMT -5
Ok, my idea worked... kind of.
The other positions work but the rhythm position is still a lot louder. Any ideas?
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Post by wolf on May 27, 2008 9:43:23 GMT -5
Hello Again Dusty, Well, maybe you should wait for others to reply, but if I encountered a problem like that, I'd start redoing the wiring completely. (Yes, that might seem like a lot of work so by all means, wait for someone else's answer.) At first you said the treble pickup didn't work at all, now both pickups work but the rhythm is louder. There are a lot of factors that could be causing that - the switch, the pots, and even the wiring itself might be "shorting out", etc. Then again, if you are having this guitar refitted with new pickups, why are you trying to get it to work now, when in just a short time, most of your efforts will be replaced?
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Post by D2o on May 27, 2008 9:57:10 GMT -5
Hello Again Dusty, Well, maybe you should wait for others to reply, but if I encountered a problem like that, I'd start redoing the wiring completely. Me too (but not with the SeymourDuncan schematics I pointed you to - sorry about that) He wants to learn is all. Good on him - go fer it!
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Post by dustyboy316 on May 27, 2008 15:47:44 GMT -5
Yup, I'm just trying to learn. When I get out of school I plan on building a guitar and wiring is probably my weakness. I get it, but can't trouble shoot too well.
I doubt there is shorting unless it occured after I "fixed" it. But wouldn't there be no sound if it was shorted?
Oh and those SD diagrams may have a use, I have a SD pick up coming in the mail, but I'm probably selling it, because of money (just bought a Blackheart tube amp too).
Anyways if I use a multimeter can I check if the pick ups shorted?
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Post by newey on May 27, 2008 20:08:51 GMT -5
DB- Yes, follow the method in the link. You can use an old guitar cable (that you're willing to sacrifice), cut off one (working!) plug and strip the wires back so as to attach your meter. Follow ChrisK's directions and post your results. You'll need to modify the procedure a bit but it's basically the same idea. Post your results for each switch position. But, more basically, I was expecting to see a loose wire on the switch. Or perhaps just a bad solder joint, not wholly detached but still no contact. I would not expect that the switch would need to be rewired, it was working (I assume) before you took it in and there wouldn't be much reason for a tech to touch the switch wiring if'n he was just fixing the output jack. If the wires weren't changed, your changing them to a different configuration is not likely to solve the problem. I can't tell much from your switch photos, but first, I would compare the switch in your guitar with the one on the Ace Frehley diagram, since you have been told that yours is essentially that guitar. The diagram shows a std LP toggle switch, which has only 3 terminals (or "lugs", as they are sometimes called) Is yours the same? If it is, rewire it according to the diagram. If not, further discussion is needed. I suspect the latter from your photos, but again, I can't tell much. And, BTW, I am not understanding your references to "potentiometers" when discussing your switch wiring.
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Post by ashcatlt on May 27, 2008 21:50:56 GMT -5
First thing to check if you've got an apparent volume mismatch between 2 individual pickups is pickup height. Why? Because it's a lot easier than messing with the wiring, and you can mess with the wiring all you want, but it will never fix a pickup height issue.
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