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 Post subject: Emg PJX Pot problems
PostPosted: July 20th, 2017, 5:46 am 
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Joined: May 3rd, 2017, 2:17 am
Posts: 32
Hi Guys,

I decided to do an install of the active pjx set from emg,it's a solderless kit and I've had nothing but problems from the start,I've gone over the schematic numerous times and no matter what I do I cannot get the pots to work.It's wired as V/V/T,the weird thing is I can have all the red power wires plugged into the power bus and the pots unplugged,and I still get sound,yet when I hook the pots up,I get the exact same thing,low output no volume or tone changes and when I touch the pots I get a weird buzzing sound....I'm really thinking My pots are no good but you'd think at least one of them would work,what are the chances of two bad pots? They are the 250k pots and I also used the jack that came in the package.I will include some photos.

Thanks Guys.


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 Post subject: Re: Emg PJX Pot problems
PostPosted: July 20th, 2017, 6:08 am 
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Joined: August 1st, 2015, 6:36 pm
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Location: Cambridge, MA
Very strange.

I would like to take a look at your pictures. If you could post the schematic you're following, that would help too. I was an electrical engineer in a previous life and I've been inside a few guitars, so I might be able to see something.

The odds of one or both of your pots being bad are exceedingly low.


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 Post subject: Re: Emg PJX Pot problems
PostPosted: July 20th, 2017, 6:11 am 
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Is this the circuit you're trying to create?


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 Post subject: Re: Emg PJX Pot problems
PostPosted: July 20th, 2017, 6:16 am 
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Yes that's the correct schematic and I've tried to upload the photos four or five times now and its not letting me,I'll try again


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 Post subject: Re: Emg PJX Pot problems
PostPosted: July 20th, 2017, 6:25 am 
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its not letting me upload photos
Image
<blockquote class="imgur-embed-pub" lang="en" data-id="6lMKnX5"><a href="//imgur.com/6lMKnX5"></a></blockquote><script async src="//s.imgur.com/min/embed.js" charset="utf-8"></script>


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 Post subject: Re: Emg PJX Pot problems
PostPosted: July 20th, 2017, 6:34 am 
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Location: Cambridge, MA
Let's see....

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 Post subject: Re: Emg PJX Pot problems
PostPosted: July 20th, 2017, 6:37 am 
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Are your "R" and "T" connections swapped on the jack? Hard to tell from the pic.


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 Post subject: Re: Emg PJX Pot problems
PostPosted: July 20th, 2017, 6:47 am 
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no,ive tried them both ways,would grouding have aything to do with it? or not having the pots in the actual pickguard? they are just hanging loose right now,I am thinking the pots might need to be mounted with the shielding, to work maybe


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 Post subject: Re: Emg PJX Pot problems
PostPosted: July 20th, 2017, 6:59 am 
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The white wire definitely has to go to "T" (tip). That's your signal.

When you plug in a mono instrument cable, it will make a connection between "R" (ring) and "S" (sleeve). This is like the power switch--removing your cable disconnects the battery.

You're not using a stereo cable by any chance, are you?

Everything should be grounded via the black wires, so you shouldn't need extra grounding for the pots for the pickups to work. The black wires will always be ground, and the red wires will always be 9V. If you have a volt meter, it may be helpful to make sure you can see 9V everywhere 9V is supposed to go.

What diagram are you using for connecting the pickups? Try disconnecting your J for now (when disconnected, it won't affect the rest of the circuit), and double-checking that your P is wired correctly:


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 Post subject: Re: Emg PJX Pot problems
PostPosted: July 20th, 2017, 7:15 am 
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Please forgive the dumb question, but you have a battery connected, yes? I can't see it in the picture.


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 Post subject: Re: Emg PJX Pot problems
PostPosted: July 20th, 2017, 7:23 am 
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yes the battery is connected i get output,the pickups work, its the pots when i roll them on/off tone /volume nothing happens the sound nor tone changes its just a constant straight output.


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 Post subject: Re: Emg PJX Pot problems
PostPosted: July 20th, 2017, 7:27 am 
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You might very well have some bad parts.

One solderless kit I received had a bad bus board. That was infuriating to troubleshoot.

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 Post subject: Re: Emg PJX Pot problems
PostPosted: July 20th, 2017, 7:37 am 
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Location: Cambridge, MA
If you're feeling clever, you could try isolating different parts of the circuit.

For example, you could plug the Output Cable into the Neck Volume pot where the cable to the Bridge Volume pot goes. The all you have is P pup => vol pot => Jack plus the battery in the circuit.


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 Post subject: Re: Emg PJX Pot problems
PostPosted: July 20th, 2017, 9:48 pm 
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Joined: May 3rd, 2017, 2:17 am
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fixed!!! turns out it was the copper sheilding messing the signals up!


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 Post subject: Re: Emg PJX Pot problems
PostPosted: July 21st, 2017, 3:27 am 
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Nice! Glad it worked out.


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 Post subject: Re: Emg PJX Pot problems
PostPosted: July 21st, 2017, 7:28 am 
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I just saw this thread. I had a similar issue and yes, the cavity ground copper ground / paint touching a part of the board/pot of my BQC faulted and drove me nuts. I moved the pot a little and placed a shim in between the BQC board/pot and everything worked clean.

You must ALSO be aware when wiring these and don't have a battery connected while completing installation. My luthier fried a few preamps due to this. Plug battery in last. EMG might have fixed this by now as this was near 5 years ago and I reported it to my guy there.

I understand your frustration on this one.


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