I Need the Resident Wiring GURU PuhLease!

[Drak]

HAAALP!

Bastard MF'in %*&#*& Piece-O' Steenkin' Trash!

I need someone who's familiar with the EMG controls, or the resident electronic GURU.

Wiring up the Shark, got everything done and there is ONE freakin' problem and I can't quite figure it out although I can isolate it down to a specific area.

OK you wiring guru's, here's the skinny...

Pkps (2 standard-wired HB's) > 3-way Gibson toggle > volume pot > SPC control > Afterburner > output jack.

PS, until the EXG shows up, I figured I'd stick in a SPC control I had lying here. They wire up the same way.

I get no sound unless I pull up, then turn the A-burner up ALL the way, then I can hear a very faint signal, but enough signal to let me know a few things...

1. the 3-way is working, and the pkps are wired correctly. I can toggle the switch and hear it switch the pkps, and I can take a screwdriver and tap them and hear enough of a sound to know that they are wired right and working.

So...pkps are OK, 3-way toggle is OK.

Let's skip the volume pot and SPC (this is where the problem is I think)

And jump on to the A-burner. The A-burner is also working, with what little signal is being fed to it, as when I pull it up and rotate, I can hear the signal come up (but very, very faint and clean)...so the A-burner is OK, and the output jack is OK else I wouldn't hear the effects of the 3-way and a-burner.

So, that leaves the area of the volume pot and the SPC control. Also, the problem is with the hot signal, not grounds. There is no weird hums or buzzes, it's a lack of a hot signal. The hot signal is getting diverted or cut off or something somewhere in this area between these two.

Either I wired the volume pot wrong or the SPC wrong, or the SPC be broke down.

OK, let's look at the SPC.

Blk- ground- that's going to ground.

Red- battery hot - hooked up to all the other battery hots, that's OK (at least I think)

White and green - this is where the signal comes in and exits the SPC control, and I think it's wired correctly by the diagram but this is the trouble point, so I'm wondering...

...and the volume pot. right side tab bent back to ground and all other grounds hooked up here (pretty normal)

OK...I've got the left hand lug being fed by the 3-way toggle hot output (remember, pkps > 3-way > volume > SPC)

and the center lug going 'out' to feed the 'in' of the SPC control.

Between this point on the volume pot and the signal coming in and going out of the SPC is where the problem lies, the hot signal is getting lost somewhere in that section.

I think one or the other is wired backwards or something.

Many thanks for any troubleshooting tips/advice. I think I wired something backwards in this section.

Brand new battery.

The SPC was bought used from the 'bay, but I bought an EXG from the same guy (I bet he broke down a DG-20 and parted it out) and the EXG works fine.

Help turn my shark into the JAWS OF DEATH!

[Brian]

Although I'm not an expert on EMG's I've only done a few of them I think your main problem is you have a ground wire to begin with?

Seem's I remember the EMG as being a closed curcuit loop from + to - and no ground wiring at all. Wait till Wes get's here he's the resident Guru on them

[westhemann]

yeah brian is right you don't ground to the bridge.you have to wire it exactly as the diagram sent by emg shows and with the same pots that they send with the pickups.

if you do have it grounded to the bridge then disconnect that.if it doesn't help or if you don't have it grounded then it pretty much has to be the hot lead like you say.try a different battery first,i had one come out of the brand new package dead once,it really threw me off until i figured it out.then replace the battery connector plug(i don't know the proper name.)each pickup comes with one so you should have an extra.

if all that doesn't work then replace the volume pot(again you should have an extra)it is really easy to overheat the volume pot when you are soldering those two big braided wires to the back of it and that will also cause problems(i accidently dsid this with my v)

good thing is every emg pickup comes with it's own pots soi you always have extras.

and like i said the values of these pots are different from the passive ones so they must be used.

hope that helps

[daveq]

I have a guitar that I built with an EXG in it with an 81 and 85. If you are still having trouble, I can at least tell you how the EXG is wired (hoping that the SPC wires the same way). It's a bit of a pain to get at it so let me know if you still need help.

Dave

[Saber]

According to the EMG website, the white wire is the input and green wire is the output of the SPC. Since you didn't mention this in your post, I figured you might have them reversed.

Or did you happen to connect the SPC white wire to the Afterburner white wire, or the SPC green wire with the Afterburner green wire? I think what you want is the volume control center lug to the SPC white wire, the SPC green wire to the Afterburner white wire, and the Afterburner green wire to the output jack. If that's what you have then one unit may be defective.

To isolate the problem, the logical thing would be to remove either the Afterburner or the SPC from the circuit and see if your signal gets to the output jack okay.

[Drak]

wes: my apologies, I should have stated that this is a hybrid circuit, using regular HB's, regular Gibson-style 3-way, and and regular 500K pot, then it switches over to EMG mainframe into the SPC, A-burner, and EMG output jack.

I should have mentioned that. And I will stick a new battery in there just to check. Thanks.

Dave, nah, don't bother, I don't want you ripping your guts apart, I'll figure it out but thanks for the offer, much appreciated.

Saber, that is some useful information and I bet I'll be able to get further with it armed with that. Thanks a truckload.

My main concern was the volume pot. I'm 'pretty' sure everything else is OK (not 100% tho) I've wired a few circuits very similar to this one before, they all worked fine right out the gate, so I'm familiar with doing what I'm doing, but the volume pot/3-way Gibson toggle is a bit different than my standard Fender-styled 5-way switch...

Just put in a 14 hour day, I'm beat, I'll take it up tomorrah, thanks all!

[westhemann]

also when you order most 3 way toggles they have 4 contacts at the back.the middle 2 contacts should be bent until they touch each other and connected to the far left terminal of the volume pot.make sure you have that correct

[Drak]

Yes wes, that part is all correct, but thanks for the check, that helps me to know the volume pot 'is' wired correctly then.

I appreciate the help. We'll git it figgered out soon.

I'm just too damned lazy to pull one of them out, I'd rather try to hunt the problem down without unsoldering a bunch of stuff. I usually put heat shrink on my connections, and it's a bit of a PITA to cut it back off...

I think after talking it out and the input back from you guys, I think I'm going to swap the 'in' and out' wires on the SPC. Something tells me that might be it.

You know, when you buy something used, you never know what the guy in front of you did to it.

[Brian]

You know, when you buy something used, you never know what the guy in front of you did to it.

How true

[Drak]

OK, I'm gonna fire up the soldering iron shortly, but I just got home from work and the weather is stunning today, I've got the guns out and shooting finishes right now.

But I have a question for the circuit-mongerers out there, referring to the EMG practice of disconnecting the ground wire to the bridge for the human shield grounding thang.

Why do they do this, and what effect would it have if you DID connect that ground back up, AND using an EMG circuit?

Would your body eat up current and drain the battery faster?

I really have no idea, and my logic can't figure out why it would really affect anything at all...but I would like to know.

[westhemann]

the thing is that the ground to the bridge in a passive system is as far as i understand it only to protect the player from electrical shock.in an active system the danger of electrical shock to the player is not a factor therefore it is not needed.

i really don't know if grounding the bridge affects the active system in a negative way,but they say not to hook it up so i don't.and i do prefer not having to worry about grounding the bridge on the guitars i build.

on my very first guitar i didn't have internet or any knowledge of guitar wiring so i hooked up my passive pickup directly to the output jack because that's the onl;y way i could figure out to make it work and i didn't have the money to buy a guitar but i didn't know you should ground the bridge so i didn't.that guitar shocked me every time i plugged it in on a high humidity day.

i didn't know how to fix it so i just borrowed my grandpa's rubber boots when i played.

that was a looooooong time ago.

[Drak]

THAT DID IT THAT DID IT!!!!!!!!!!!!!!

WOO-HOO!!!!!!!!!!!

Switched the in and out wires on the SPC and IT BREATHED LIFE!!!

OH MY GOD, IT'S ALIVE, IT'S A-LIVE HAHAHAHA!!!!!

BUT!...it's too damned late to be able to do anything productive with it here at home tonight.

But, everything works! Pkps work fine, toggler is A-OK, A-burner is good, SPC is working.

Thanks everyone, I knew we'd get 'er done!

I think it was the 'Uli Jon Roth' Mojo workin' for me too, I've got the Scorps' 'Fly to the Rainbow' playin' right now...Thanks Uli!

[westhemann]

congratulations.