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03-14-2013, 01:00 PM
|  | Functionless Art is Merely Tolerated Vandalism | | Join Date: Dec 2010 Location: Saskatoon, Saskatchewan | | | Jaco Bass has no output!
So I have let this Jaco (Artist not CS) bass get neglected for the last month or so (I know it is a tragedy... don't ask). I popped it out to take some pictures for another TBer to see a shielded Jaco and when I plugged it in to rock it out I had no output. So I needed to open it anyways now to see what is going on.
Everything appears to be wired correctly still and it doesn't appear as though any of the wires have lost their connection so I don't know where to start. I have an electrician that can help me but it might take him a few days to get some free time... I'd rather not wait, now that I look at this bass again I am dying to play it!
I suppose a pot or pickup could have failed but I have never seen that in my day, I thought it took decades for them to fail. I have a good multi meter handy if I can check this out easy enough.
This is the closest thing I could find to schematics, if anybody has any better schematics I would appreciate them but I think this is as good as it gets.
Thanks in advance!
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03-14-2013, 01:25 PM
| | | | My best guess is the tip connection on the jack (long bent metal that touches the tip of the guitar cable) isn't making a connection. Are any of your pots loose?
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03-14-2013, 01:31 PM
| | Functionless Art is Merely Tolerated Vandalism | | Join Date: Dec 2010 Location: Saskatoon, Saskatchewan | | | No, nothing lose at all. I tugged on all the wires and such as well. I'll go check the tip right now.
EDIT: Tip fits perfectly into the jack, makes a great connection.
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Last edited by DiabolusInMusic : 03-14-2013 at 01:35 PM.
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03-14-2013, 01:32 PM
| | Functionless Art is Merely Tolerated Vandalism | | Join Date: Dec 2010 Location: Saskatoon, Saskatchewan | | | I should add that I had it in it's case, back down, with my Carvin case generally on top. If that might have caused something to shift I don't know, but I don't think that had any negative effects.
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03-14-2013, 01:34 PM
| | Registered User | | Join Date: Jan 2012 Location: Dayton, Ohio | | | Have you tried testing it with the plate off and the wiring hanging out? I'm thinking that maybe something is touching the shielding when you put the plate back and that its causing a short.
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03-14-2013, 01:46 PM
| | Functionless Art is Merely Tolerated Vandalism | | Join Date: Dec 2010 Location: Saskatoon, Saskatchewan | | | Yeah, I was testing it with the plate off, no strings and the pickups are not even screwed down. The linked post has some pics of the shielding job but they are not the greatest.
I was just tapping on the pickups to see if they put out noise and didn't get anything.
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03-14-2013, 02:10 PM
| | | | One of your solder joints may have gone bad, or you may have build up on your output jack. You clean the jack's connecting parts off with a pencil eraser, that will help to eliminate a bad connection at the output jack. |
03-14-2013, 02:16 PM
|  | Registered User | | Join Date: Dec 2009 Location: California | | | You've tried with different cable? |
03-14-2013, 02:18 PM
| | Registered User | | Join Date: Sep 2007 Location: London, England | | | It could be sulking due to neglect?
Davo |
03-14-2013, 02:23 PM
| | Registered User | | Join Date: Jun 2008 Location: Close to Los Angeles, CA | | | Sounds like the jack is touching the shielding. |
03-14-2013, 02:45 PM
| | | Quote:
Originally Posted by line6man  Sounds like the jack is touching the shielding. | That was my next guess. 
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03-14-2013, 05:19 PM
| | Functionless Art is Merely Tolerated Vandalism | | Join Date: Dec 2010 Location: Saskatoon, Saskatchewan | | | Ok, so I now have output. I had the control plate off and was just spinning the knobs and touching stuff to see what kind of reaction I got. The tone knob gave me a cracking sound and the bass came to life, like a piece of debris had come loose. I sprayed some deoxit in the pot but the pot still has more friction to it than the volume knobs. Although from the sounds of it, I am pretty sure the tone knob is working fine.
The bridge pickup volume seems to work fine but the neck pickup/pot doesn't seem to do much. The bridge pickup is only audible with the amp absolutely cranked. Before anybody says it, I know that pickup should be off anyways and it usually is but I want it to respond properly.
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03-15-2013, 09:27 AM
| | Functionless Art is Merely Tolerated Vandalism | | Join Date: Dec 2010 Location: Saskatoon, Saskatchewan | | | Nobody? I am sure the neck pickup should have more juice to it, regardless of it being a Jaco signature.
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03-15-2013, 12:42 PM
|  | Registered User
Endorsing: Ampeg | | Join Date: Apr 2005 Location: Apopka, FL | | | I've burned out cheap pots by heating them up too much when soldering. It can be done.
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03-15-2013, 12:50 PM
| | Functionless Art is Merely Tolerated Vandalism | | Join Date: Dec 2010 Location: Saskatoon, Saskatchewan | | | Good to know Jimmy, although I should add I didn't actually add anything to the pots or wiring, just added shielding and wires to ground them. The control circuit is factory fresh (to my knowledge, I did buy used)
I looked into how to test a pot, it involves me removing it from the circuit.
Is this a symptom of a failing pot? I just want to know before I go through the hassle of removing a pot.
I took the bass out last night to vocal practice and found when I turn up the amp I get a hum, like an interference hum, that doesn't go away when I touch the bridge/metal. It also does not get louder. It also makes a static electricity pop, which I know comes back to shielding as I have removed that from basses before.
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03-15-2013, 05:41 PM
| | | | I thought you meant it had no output plug and I had to check if it was April already. . |
03-16-2013, 10:24 AM
| | Functionless Art is Merely Tolerated Vandalism | | Join Date: Dec 2010 Location: Saskatoon, Saskatchewan | | | Ha, no it has the actual jack. Which is working.
I still have minimal output from my neck pickup and a constant, quiet, hum. Hopefully I can get this looked at today with my electrician.
Nobody? I am thinking I need a new thread for more answers.
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