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 Post subject: MPC output jack
PostPosted: Thu Sep 25, 2008 11:46 pm 
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Joined: Mon Jun 02, 2008 1:05 pm
Posts: 9
Hello gang,

I never resolved the issue of the 9V battery dieing in my bass even though I keep it unplugged. I have to physically remove the battery so it doesn't drain. I know this has to do with the stereo output jack. I looked at mine and it looks like a previous owner must have done some rewiring, as I see old solder, new solder, new cables and one of the three tabs on the stereo 1/4" jack is not connected to anything, but has old solder on the tab.

Can anyone give me some insight here as to how this should be wired? I'd love a photograph or two if any of you out there has a correctly-working x-610/620. Email me directly at growlyman@(NoSpam)gmail.com.

Thanks.

Chris


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 Post subject: Re: MPC output jack
PostPosted: Fri Sep 26, 2008 4:26 am 
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Joined: Thu Feb 07, 2008 5:52 am
Posts: 1924
Location: Ann Arbor, Michigan
Well, I'm no electrician, but here's my two cents (worth) of advice. Get yourself a Volt/Ohm meter, $10-$20 at Radio Shack, or if you want, $50 on eBay for a nice used Fluke. If the output jack has three pins, thats a TRS or 'tip/ring/sleeve' standard stereo jack, as opposed to the standard two conductor jack on most guitars. It would seem that when your non-stereo guitar cable is plugged in, it shorts the 'Ring' and 'Sleeve' pins together because there is no 'ring' on a mono Phone plug, allowing power to the device.

Put your meter on the different pins while you plug in your guitar cable, and find out which pins behave this way (conductivity when plugged in, infinite resistance when unplugged) and you have at least determined which pins are involved. You may be able to determine this just by looking at the jack, and frankly if the wiring has been played with, or if it's wired into the guitar while you do these tests, you may get unreliable results.

Now here's where I get confused myself, as I don't know if they are shorting the positive (hot) or negative (ground) of the battery with this 'switch', or if it even matters? Maybe someone else could chime in.

As another option, you could basically insert another physical switch on one of the battery leads so that you could manually switch the battery on or off from the front of the guitar, and never worry about unplugging your cable when you're not using the guitar. I hope this helps, Mike.

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 Post subject: Re: MPC output jack
PostPosted: Fri Sep 26, 2008 7:14 am 
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Joined: Thu May 03, 2007 9:32 am
Posts: 1024
Location: NYC
I have an Outlaw bass that I am working on restoring. The electronics are intact. I will try to take some photos this weekend if that would help.


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 Post subject: Re: MPC output jack
PostPosted: Fri Sep 26, 2008 9:42 am 
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Joined: Mon Jun 02, 2008 1:05 pm
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Workingman wrote:
I have an Outlaw bass that I am working on restoring. The electronics are intact. I will try to take some photos this weekend if that would help.


That would be very helpful!

Chris


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 Post subject: Re: MPC output jack
PostPosted: Mon Nov 10, 2008 12:05 pm 
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Joined: Mon Jun 02, 2008 1:05 pm
Posts: 9
Hi again all.

Workingman has given me more insight into the wiring of the MPC input jack. From that we've confirmed that a previous owner did some rewiring, as my TRS jack only has 2 leads soldered to it instead of the original 3. So what I need to find out is where exactly all 3 wires solder to from their points on the jack itself. I'm willing to be this is the reason the battery drains even when not plugged in.

HELP! Please? Photos? Tech drawing? Assembly diagram? Anything. Please please please????

Thanks.

Chris

Workingman wrote:
I have an Outlaw bass that I am working on restoring. The electronics are intact. I will try to take some photos this weekend if that would help.


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 Post subject: Re: MPC output jack
PostPosted: Tue Nov 11, 2008 6:31 am 
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Joined: Thu Feb 07, 2008 5:52 am
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Location: Ann Arbor, Michigan
I do not own a Outlaw or any 'powered' Electras for that matter, but lets look at this logically. We know that the jack is basically being used as a switch, when a (mono) plug is inserted, it is shorting the 'Ring' and the 'Sleave' together on the Stereo jack. I would wire the Negative lead (usually black) of the battery directly to the 'Ring' tab, and the guitars ground to the 'sleave' tab. Again, logically, if the plug is not inserted, the battery circuit CAN NOT be completed, so there should be no drain.

Another option, as I said above, is to put a manual switch in line with either of the Battery leads that could be manually flicked 'on' when the instrument is being used. If the circuit is broken, the battery should not be draining. I'm not Mr. Spock, but logically, this should work. Cheers, Mike.

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 Post subject: Re: MPC output jack
PostPosted: Tue Feb 03, 2009 10:53 am 
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Joined: Wed Nov 19, 2003 4:58 am
Posts: 932
Location: Southern Indiana
Ever get this resolved?

The battery's ground (black) wire should go to the "switch" part of the jack. That means the "stereo" or middle part of the jack. The other normal "ring" connector is grounded, and the "tip" is the HOT for the signal.

Move it to the input jack to the "switch" tab of the stereo jack. That way, when the guitar is plugged in by a mono jack, the middle connector touches mono jack to the "ring" of the jack that is connected to the Ground. Unplug it, and the battery black wire is not touching the ground.

If the black wire from the battery is grounded elsewhere, that would be why unplugging your jack does not keep it from draining the battery.

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 Post subject: Re: MPC output jack
PostPosted: Tue Jul 21, 2009 11:26 am 
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Posts: 9
Geez, did I take THIS long to do the repair? LOL! What can I say? My day job keeps me busy.

First, I wanna thank you guys for your input on my output! ( :rofl: ) I have a lot of experience with wiring, soldering and repair work, but electricity still throws me sometimes. But all your troubleshooting tips made perfect sense to the tech in me, so it was easy to follow. The online schematics I found on this site was useful as well. Thank you thank you.

The confusing thing about my particular instrument is the wiring of the ring and sleeve. On a standard mono instrument, your connections are only going to be tip and sleeve. As we know, these MPC instruments have the ring connection as well to complete the circuit to activate the battery to the electronics. Great design too. What was throwing me is that when I connected the leads for the pickups to the tip and sleeve connections of the output jack, as if it was a standard mono connection, the bass wouldn't play. Just buzz, and pretty bad. Seems the output on my bass only works with the connections on the tip and RING. More so, reversing the polarity also shut down the output (mind you, this is all without engaging the active module circuitry). That's confusing, but perhaps I'm not getting enough of my anti-oxident vitamins and my caffeine ran out at 2:30 in the morning when I was doing this and I was seeing backwards!

Anyway, since the bass made it clear to me it was only going to make pretty noises in a very particular wiring output of Tip-hot/Ring-ground, I figured the sleeve tab would have to be the only option for the battery ground, which the previous owner had soldered to the casing of the tone pot (not sure why this kept the circuit hot while the instrument sat, but it makes sense that it should make the battery drain). So, I attached the battery negative lead to the sleeve tab of the jack and everything activated. Again, switching the bass ground on the ring tab with the battery negative lead on the sleeve tab deactivated everything. Is that strange? Again, not an electrician.

Long story less long, bass is reassembled and the battery is no longer draining. I've had it hanging on the stand for the last four days, with the module switches engaged, and it's not draining. Working to form. So I'm just gonna figure the bass is working like a Windows computer; not sure it's set up correctly, but it's working and I'm not changing it! :eek2:

So, my Chris Squire replica is finished, as far as I wanna go anyway. You can see a picture here:



http://www.facebook.com/photo.php?pid=2 ... =731886479

Since I took this photo, I changed out the knobs to two gold saucers and two black saucers to make it look more Squire. I didn't want to get a mirror pickguard cuz that will never look clean. Black is fine. But I do wish I knew what the two additional knobs are on Chris' bass, as he has 6 controls as opposed to the stock 4. Plus he's got mini switches, which I just might change out on this instrument if I find a suitable replacement. Other than that, my last find for the instrument will be an original Badass (version I) bridge in gold/brass finish .... I didn't realize those were near-impossible to find.

Tempus Fugit my friends. Rock on everyone!

Chris


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 Post subject: Re: MPC output jack
PostPosted: Thu Jul 23, 2009 1:24 pm 
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Joined: Thu Feb 07, 2008 5:52 am
Posts: 1924
Location: Ann Arbor, Michigan
Looks cool man, saw the modification on lower horn, were you going for a Rick look (about all I ever see the 'Yes' man playing)? Didn't the Outlaw basses have white knobs originally? I'm glad that your battery isn't draining all the time now. I have a Charvel Model 4 that I have to replace the battery in every two or three months, whereas the Model 4 that I bought new goes years between swaps, maybe I'll get in there and see what the battery is hooked up to now! Congrats.

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