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Post by gfxbss on Nov 30, 2006 18:15:34 GMT -5
alright, just to make sure, you said that i should test on half and no vol on 200K and 2000k. at any rate, both of these registered 0.000 across the board. however, if i ran half vol at 2K(I assume this is what you meant?), i had 0.009 across the board. w/ no vol, i again ran 0.00 across the board....
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Post by JohnH on Nov 30, 2006 21:32:26 GMT -5
If you are getting these very low readings at all volume settings, then it suggests a short circuit at the jack socket or volume control. Anywhere else, and the readings at mid volume settings would have been much higher. Maybe a bit of shielding material touching something it shouldnt? You could unsolder from the jack and test to the bare wires from the guitar that were connected to it - then lift out the control panel, and test again and look for shorts.
If you need to test for sound, with the guts out of the guitar, just plug in and tap one of the six poles on a pickup carefully with a screwdriver. It should make a significant thump, it that pup is connected.
cheers
John
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Post by gfxbss on Nov 30, 2006 22:25:46 GMT -5
alright, thanks for the help. ill try to get to that tommorow after i get off of work. i am familiar w/ the screwdriver test, so that shouldnt be a problem.
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Post by gfxbss on Dec 1, 2006 17:24:27 GMT -5
alright, i took out the jack and i still got 0.02 across the board.....
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Post by JohnH on Dec 1, 2006 18:10:48 GMT -5
Better take the pickguard right out, so it can be probed. if possible, could you post some photos?
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Post by UnklMickey on Dec 1, 2006 18:19:02 GMT -5
hi Tyler,
i'm about to bug out for the weekend. i thought i'd point you in the right direction before i go.
i assume you made the correction i pointed out in reply #7.
first, disconnect the 2 wires that go to the left (in the drawing)terminal of the volume pot. measure with the probes on the right and center terminals of the volume pot. when counter-clockwise you should read zero. when clockwise, the full value of the pot. if that is O.K. then go to the next step.
with the 2 wires you disconnected, measure each one separately to the ground of the circuit. if the coil-split switches are in their center-off positions, you should read about 8000~20,000 ohms, depending on how "hot" the pickups are. about half that, if the coil-splits are engaged. if the volume control was okay, then one of these measurements will be near zero. (or both if you really messed up.) that will narrow down the where the problem is.
good luck,
unk
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Post by JohnH on Dec 1, 2006 18:48:06 GMT -5
Unk has pointed out that as its an Epi, probably no pickguard. Thats easier, you can take the back off to get to the wiring and probe without destringing J
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Post by gfxbss on Dec 1, 2006 20:11:07 GMT -5
alright here is what i got.
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Post by JohnH on Dec 1, 2006 21:12:18 GMT -5
OK - did the first check that Unk posted above work out, measuring right and centre of volume pot? Your table above looks fine for the neck. When on the bridge, it reads O/L, I'm not sure what that means with your meter. Is that the same as when the probes are not connected to anything? (an open circuit) or is it as if the probes are touching (a short circuit).
John
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Post by gfxbss on Dec 1, 2006 21:18:19 GMT -5
it means that there is an open circuit
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Post by UnklMickey on Dec 1, 2006 21:43:39 GMT -5
weird stuff eh?
you went from having everything shorted, to having the bridge portion of the circuit open.
did you check the operation of the volume pot. i wonder if you also have a short between the wiper and the ground. if you are using a shielded cable on the output, that can happen easily, if you overheat the shield. it melts the insulation that separates it from the inner conductor.
anyway, using the schematic, work from where the connections from the bridge pickup first connect the circuit. you didn't label which was bridge on the diagram. is it the one with the phase switch? if you still measure open circuit there, you have the wrong connections to the coils, or your pickup is stuffed.
if you can get things working correctly in the bridge portion, make sure you check the volume control, before you connect everything back together.
L8r,
unk
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Post by gfxbss on Dec 2, 2006 10:39:34 GMT -5
alright, so i just tested my vol. i just left the ground lug grounded and then did the middle(out) lug. on full, it ran only about 0.02. w/ vol all the way down, it ran 0.00.
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Post by UnklMickey on Dec 4, 2006 8:55:45 GMT -5
hi Tyler,
something is stuffed at your volume control. we need to figure out what is going on there, as well as in your bridge circuit.
let's work on the volume control first.
with the volume control at "5", what do you read from the wiper to ground? how about from the cw terminal (the one you took the 2 wires off) to ground?
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Post by gfxbss on Dec 4, 2006 17:41:48 GMT -5
alright, if i have the volume at half, then the wiper reads 0.01 and the cw reads 0.03. i noticed that w/ some other volume pots i have laying around, if i have it all the way turned down, then it reads 0.00, but if i have it turned on anything else, it reads an open circuit. that goes for botht the wiper and the cw....
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Post by JohnH on Dec 4, 2006 18:54:39 GMT -5
Volume pots are usually either 250k or 500k, generally 500k with humbuckers, To measure their resistance, you need a meter setting of 2000k, then on a good pot, which is disconnected, you should read 0-max, (ie 0-500k) from centre lug to one of the outer lugs, as you turn the pot. J
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Post by UnklMickey on Dec 5, 2006 12:18:55 GMT -5
if i had to guess, i'd say it sounds like maybe you are fairly new to soldering. either there are blobs of solder bridging the terminals of the pot together, or bridging the terminals to the case, or have dripped down and are touching cavity shielding?
as John mentioned, the reason why you read open circuit, was because you need to select a higher range on your meter, when measuring the resistance of a pot.
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Post by gfxbss on Dec 9, 2006 11:12:40 GMT -5
sorry ive taken so long to get back to you... i picked up a push pull and a three way pup selector switch and am trying to incorporate them into it.... let me know what you think of my schematic.
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Post by JohnH on Dec 9, 2006 14:47:15 GMT -5
The digram appears very small, and has a link to it, but it does not lead to a larger version. Your earlier diagrams were easier to see.
This seems to be the previous design, with Unks fix, moved to being with a push/pull pot for the phase switch. As such, the top left connection from the phase switch to the on-off-on and hot, should be moved to centre left. The three way switch is not in there yet, but could be added. Instead of having wires direct to the volume control from the two on-off-ons, take them instead from on-off-on's to the outer lugs of a three-way toggle switch, and then connect itscentre lug to the volume.
But what are you going to do with the earlier problems of resistances and missing sounds? Did you fix these? If not, and if this is a point at which you are making some changes to the wiring, it would be a good opportunity to get your head around the resistance measurements, and then unwire it all and start clean. Measure the pup coils seperately, and build up the circuit stage by stage, checking that everything is connected properly If you can break it down into verifiable stages, and confirm each one before moving on, it is much easier to trouble-shoot.
A good intermediate stage would be to install each pup wired only to the on-off-ons and nothing else. Then measuring across the outer lugs of the on-off-ons, you should read either the full humbucker resistance (about 10k to 15k), or half that if the on-off-on is set to a coil cut position.
good luck
John
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Post by gfxbss on Dec 9, 2006 15:12:33 GMT -5
alright, this one is updated.
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Post by JohnH on Dec 9, 2006 19:13:14 GMT -5
OK, looks like that should work!
cheers
JOhn
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Post by gfxbss on Dec 10, 2006 11:36:16 GMT -5
alright, got it all wired up. two problems, one is that the bridge coil tap switch. it only works if it is on the south coil. this worries me because this is the switch that is directly off of the pup. i dropped another switch in only for the same results. both of them read good on my multimeter...
next problem. the pups sound like they are always out of phase w/ each other.... what should the multimeter read if the pup is out of phase? w/ the push/pull in either position the multimeter still reads the same...
Tyler
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Post by gfxbss on Dec 10, 2006 20:55:26 GMT -5
alright, got the coil tap fixed. somthing had come unwired and i couldnt see it in my birdsnest of wiring.
however, i deff sound like im am permanently out of phase
the multimeter is reading 6.82 whether the pot is in our out.
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Post by gfxbss on Dec 10, 2006 22:35:20 GMT -5
SALVATION HAS COME! im not exactly sure how, but it is now working! everything is great. I want to thank everyone for being so patient w/ me. it has taken a while, but i learned a ton and am very proud that i got everything to work. i would especially like to thank Unk, Flat and John. You guys are great. here are some pics of it. And my '68 Epi Bass.
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Post by JohnH on Dec 11, 2006 5:44:55 GMT -5
Well done! Its a great feeling isnt it? Such a small space you were working in!
Now that its going, you can tell us about the sounds. Your design is unusually interesting because you have the provision to select any single Sc coil or pairs of coils. Do you hear much difference between the coils? how about combos of inner coils as compared to outer coils?
I love the Zep bass too
cheers
John
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Post by gfxbss on Dec 11, 2006 8:41:05 GMT -5
it is a great feeling, but now i dont know what to do. in a matter of 3 months i rewired the thing probably like 10 times. I think when i get the cash, im going to put a bigsby B-6 and some grover locking tuners on it....
now i have no project that i can afford. when i get the cash though, im also gonna drop some seymore duncans in an LP copy I have the wire it to a jimmy page copy.
yeah, it is a super tiny cavity, that is after a lot of expansion on it too. what would you guys suggest i use to make a new wire back? im thinking of taking the pickguard off of the LP copy before mentioned and cutting it to size....
the sound is perfect. i can hit any sound i want. one thing i wasnt expecting was when i have phase on and my neck pup selected, if i go to the south coil, it works. however, if i put it on full or north coil, i get no sound. its probably a wiring mistake on my part, but i like it more. im a huge fan of tom morrello, and every one of my guitars up to this point has had that kill switch in it. this gives me the chance to get that sound out of it.
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