grockle
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Post by grockle on Oct 10, 2007 12:16:37 GMT -5
Hey all...
I recently bought an ancient british Fenton Weill off ebay, that I'm bringing back up to working spec. Most of the hard work was removing the three spray painted coats of different coloured housepaint that were hiding the original battered red nitro
Now I'm moving on to the electrics. Both pickups work, but I got no output, though everything was wired as per the factory.
I've decided to take it all to bits, clean the components (everythings pretty corroded) and rebuild it from scratch.
I'm not sure how to post a circuit diagram here, or if it's necessary, but there are two resistors in the circuit.
What could they possibly be for? Aren't they just gonna lower the overall volume of the guitar. Would it sound better if I just left them out?
Thanks in advance for any help
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Post by ranchtooth on Oct 10, 2007 15:28:49 GMT -5
Any idea what the value of the resistors is? and also what were they wired to and how? Even a poorly drawn ms paint circuit diagram would help.
I've never heard of resistors in a guitar but we can take some wild guesses!
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Post by stratatouille on Oct 10, 2007 15:43:28 GMT -5
Any idea what the value of the resistors is? and also what were they wired to and how? Even a poorly drawn ms paint circuit diagram would help. I've never heard of resistors in a guitar but we can take some wild guesses! Bonjour, I has seen 10k resistors tied in with the tone capacitor on the tone pot ... to "smooth" things out - a bit jazzy sound. I have also heard of, but do not quite understand, using 100-150 k resistors - in parallel and/or series with capacitors, to compensate for volume vs tone (I think I saw this at singlecoil.com). Here is how you would, how you say?, "host" a diagram, as described from some nice non-french guy: "Yeah, that's easy. See those rows of buttons just above the text entry box (when you're posting, not right now!)? Check out the fourth from left, bottom row....... that'll insert the Image tag for ya. Easiest way to make it all happen is to post your picture to a hosting service somewhere (preferably on the web ), and then paste the URL link into your message. Highlight that link you pasted in, and hit the button I just pointed out. Presto! Your URL link is now active. Hitting the Preview button below the message box will show you what it looks like." M. Strat
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grockle
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Post by grockle on Oct 10, 2007 16:38:10 GMT -5
Aaargh! I've just being tearing my hair out trying to draw it freehand on a site, and it wouldn't save it Does this make sense? The parts are as follows- three pots, two pickups, two resistors, one cap, a switch and output jack 'the resistors are wired in series, one end is attached to the centre pin on the first pot, and the other end of the two resistor assembly is attached to the centre pin on the second pot. The cap is attached to the centre pin on the first pot, and the centre pin on the third pot. There is a wired coming from the JOIN in the two resistor assembly and that is one of the two wires to the output jack Other notable things in the circuit are a great big thick bit of single core wire that goes from the centre pin of the 3pole switch, and is attached to every pot along the way, and the output jack I'll try and take a photo of a hand drawn sketch, and see if I can upload that In the meantime, if anyone can make sense of that^, it'd be great
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grockle
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Post by grockle on Oct 10, 2007 16:44:17 GMT -5
oh, and its pretty difficult to work out what the resistors are...they are about a thousand years old, and the little coloured stripes have almost peeled off...i see some yellow, orange and maybe a little brown The capacitor is 0.1uf (i think...again, pretty ancient looking)
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Post by ranchtooth on Oct 10, 2007 20:12:40 GMT -5
I would guess that big thick wire is the ground. Is it soldered to the back of every pot? If so then the wire coming from the join between the resistors would be the hot output. Other than that this guitar is confusing!
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Post by ashcatlt on Oct 10, 2007 21:53:07 GMT -5
dude? if you've got a digital camera, why not just take a good picture of the guts of the guitar itself?
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grockle
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Post by grockle on Oct 11, 2007 5:38:19 GMT -5
Okay dudes...here's what I've got Can anyone make sense of that? It's only a photo of the partial electrics, as I've already started working on it...there is one error that i made on the circuit drawing- the wire going from the centre pin of the switch to the last pin on the first pot should be going to the body of the pot, not that last pin. Apart from that, that is as it left the factory (!!) - oh, and despite the slightly crummy/odd appearance, this is one hell of a guitar. Mahogany body, glued in neck, wide frets, chunky neck...and the pickups are monsters
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Post by ranchtooth on Oct 11, 2007 8:31:18 GMT -5
Based on these pictures I think the resistors are important if you want to retain the original tone of the guitar. The resistors and capacitor to the tone control are wired in parallel so I think it would make it a more pronounced treble bleed circuit at the tone pot. They also might help to reduce feedback from the guitar... it looks as if it was made back in the day when feedback was "uncool." Those pickups are beastly and I bet you could get some severe feedback and microphonics if you unleash them. If you have a multimeter it would be a good idea to check the value of those resistors.
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Post by sumgai on Oct 11, 2007 13:47:25 GMT -5
ranch, Think about this: Why does a Les Paul have it's two volume pots wired "backwards"? There's your clue for the day. ....... and grockle, Welcome to the NutzHouse! ;D sumgai
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Post by ranchtooth on Oct 11, 2007 17:51:05 GMT -5
I believe wiring the pots backwards has something to do with keeping the pickups from loading each other down. Like on a strat, the hum cancelling selections tend to be slightlier quiet cause the pickups load each other. I think thats whats going on here. I just did a little research www.singlecoil.com/docs/paula.pdfand it turns out this is a fact. The problems associated with wiring the pots backwards are: loss of treble! And we try and restore this using capacitors. Judging by the pics in the above link, those resistors are not resistors at all but rather what are called "tropical fish" caps, due to the coloured rings. I think that solves this mystery. Thanks to a timely intervention of sumgai.
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grockle
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Post by grockle on Oct 11, 2007 18:40:58 GMT -5
So i should just leave them in there? Are you SURE they are caps? I should really do a bit of reasearch to understand the whole backwards thing...
*I'm a little drunk right now...thanks for contributions, will check back in the moning...with a headache"
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Post by ranchtooth on Oct 11, 2007 19:08:52 GMT -5
I'm pretty sure they are caps, and the reason they are present is to keep some treble and tone in that guitar. So as long as your planning on keeping the guitar original, they should be left in. That said, if your not getting any signal out, theres gotta be a problem in there somewhere... You may have to do a full rewire.
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Post by sumgai on Oct 16, 2007 14:10:17 GMT -5
Those things sure look like the British version of resistors of yore. They probably came from Lucas Electric. My earlier clue attempted to point out that a Les Paul is wired backwards to prevent the total cutting off of all sound, should you turn either volume pot all the way down (while both pups are on). Which of course is what happens when they are wired in what we call the forward direction. Inherently, the backwards scheme has several things wrong with it, but the bottom line is, it works, so we don't quibble over the small stuff. But another way to prevent total loss of signal is to add some resistance to the circuit. Said resistance can be added between either the pot and ground, or the pot and jack (the wiper, in the forward scenario). Indeed, that is what's happening here, there is a resistor from the pot's wiper to the output jack. Either way has it's merits and it's downsides, but for most backyard engineers, the summing method makes the most sense. That's where you "sum" the output of more than one input by simply isolating them with resistors. In this case, each pickup circuit is one input, so we see two resistors joined together, and the joint goes to the output jack. The pitfall here is, even if you turn down both volume pots all the way, the output jack is still not at ground potential. That means that the amp's input jack is not grounded, which in turn means that most, if not all, of the noise (buzz, hum, etc.) getting into the circuit will get into the amp.... and that's a bad thing. So why did they do this, if it's not a good thing? Look again at the selector switch. See anything different? I do. It's wired to ground the pickup's hot lead when that pickup is not wanted. That's different! It works, and actually works quite well, but as noted previously, if you ground the hot lead of one pup's circuit when both are on, then all output goes to hell in a handbasket. There's that bit about 'not a good thing' again. Hence, the isolation resistors are in place to prevent that, working just as they do in any standard mixer appliance. Long story short, my suggestion would be that if you want to retain the stock appearance as much as possible, then you would want to replace the selector switch with a DP3T slide switch, such as that found on the Fender Mustang. (Common enough, easy to find.) Then I'd wire the unit like a Les Paul, as shown here: That should do the trick, unless you were planning on some mods......... HTH sumgai
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Post by ranchtooth on Oct 16, 2007 15:55:34 GMT -5
Thats one unique setup!!!
And furthermore, Lucas electric is SATAN! I have a triumph motorbike and the whole electric system goes to hell if the bike gets so much as a drop of rain on it.
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Post by sumgai on Oct 16, 2007 16:07:07 GMT -5
ranch, It's for certain that you understood the intent of my reference. ;D
sumgai
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Post by ranchtooth on Oct 16, 2007 16:48:45 GMT -5
Q: Why do Brits drink warm beer? A: Their refrigerators were made by Lucas.
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Post by gumbo on Oct 17, 2007 7:59:31 GMT -5
Ha! In a previous life restoring old British cars for 20+ years, I can confirm that Jo Lucas is widely known in these parts as "The Prince of Darkness"...
In Oz, the joke goes: Why do the Poms drink warm beer? Answer: Because Jo Lucas made the refrigerator...
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Post by gumbo on Oct 17, 2007 8:01:26 GMT -5
Hmm.. should have read Ranch's last post first...
We also found that Jo Lucas' stuff usually worked quite well until someone inadvertantly let the smoke out.....
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Post by sumgai on Oct 17, 2007 12:29:33 GMT -5
I've known that Lucas Electric is a joke for at least 45 years, and it was really old news even back then. So the wonder of it all is, why would anyone tolerate this for so long. Nations have risen in revolt for lesser offenses against sanity! Don't the British have a law that requires at least a reasonable semblance of quality in one's products, or is Lucas exempt for being a woodpile member of the Royal Family? sumgai
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Post by gumbo on Oct 18, 2007 6:57:57 GMT -5
Yep..you may actually have a point there about 'exemption' SG...my personal (professional) experience was with Lucas products made from about 1934 onwards...I had simply come to the conclusion that everyone had been so busy making tea, no-one had thought to tell them to stop...:-)
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Post by lunaalta on Oct 18, 2007 12:02:07 GMT -5
Phew, my first electric was a Fenton Weill, back in '64.
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grockle
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Post by grockle on Oct 19, 2007 15:57:49 GMT -5
Thanks for the explanation sumgai! So is it a two volume/one tone set up then? I don't really want to do any noticable mods- ie I'd like to retain the switch, and three pots, but I don't mind some alterations under the hood Worst thing is, I've stripped it down, put it back together, and it still doesn't work! Now this could be because my soldering skills are like that of a tipsy eight year old...OR could it be that the pots are buggered? I tested the resistors, cap, and switch, and despite appearances, they all passed signal. I didn't test the pots, as when plugged in originally, I was getting crackle that suggested to me that they worked Forgive the utter utter newby idiot question, but is it possible for all signal to be blocked by a dodgy pot? I really know zilch about electrics/wiring (though I never had any problems with modding my strat when I was a kid- could always get SOMETHING going ) ...another area I'm wondering if it could be problematic is the 'junction' where about four or five wires are bundled together and soldered...
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Post by sumgai on Oct 19, 2007 17:42:08 GMT -5
grockle, Yep, it do appear that way, doon't it? Hmmm, one wonders, just why would you be putting a hot soldering iron into the hands of a besotted eight year old? Surely not just so's you could compare their skill set against yours, eh? Yes, they could, but read on........... Not testing before making an assumption is the same as assuming they are bad. Depends on what the pot was dodging at the time. If it was the responsibility of passing on the signal, then yes, it is possible for the pot to go completely south, leaving you with a bald head as you snatch your hair by the fistful, wondering what the hell's going on. Don't feel so special - none of the rest of us here know anything either! ;D Not particularly more suspicious than any other solder joint that your (hypothetical) eight year old took a torch to....... or in other words, no - all solder joints are suspect, regardless of the number of wires. The big BUT here is, solder is not supposed to be the mechanical keeper of the junction, it's present merely to facilitate the flow of electrons across that mechanical junction. If the wires are just laid out side by side, sorta touching, but not really very tightly, then yes, this would be a potential trouble spot. If you're not sure, then strip as much solder away as possible, re-twist the wires together, then re-solder the new junction. HTH sumgai
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grockle
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Post by grockle on Oct 19, 2007 18:04:53 GMT -5
Thanks man...I'm determined to see this one through to the end...lost count of the number of times I've started and failed to finish a project. from what you said, I think that I've made an okay job of that 'junction' connection...that should be fine. SOOO...the big thick wire that touches all the pots...should I assume that that's not gonna be making a connection if there is a bunch of solder between it and the body of the pot? I did my best to remove as much of the solder build up, like you said, and re-applied the wire, but I'm still getting the feeling that there's not really a great connection to the pot body. Should I really go to town picking solder off the body of the pots, and wire wool them etc?
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grockle
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Post by grockle on Oct 19, 2007 18:50:08 GMT -5
Phew, my first electric was a Fenton Weill, back in '64. can you remember what model it was? Any details? They are goddamned mysterious There are a few on steve russels page, and music ground on denmark street have a couple for a grand, but apart from that I just know what turns up on the 'bay- and every one I see now seems to be a different model.
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