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Jtv 69 Battery


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I would like to hear from rchibnik about what voltage he measured at the terminals of the battery.  

The line6 battery measures 7.75 v

The Mavica battery measures 8.30 volts

L6BatterySmall.jpg

The line6 battery is on the left. Notice the shape of the pins are different and seem to be larger. The third element on the Mavica battery are larger, but both seem flush with the bottom of the battery.

 

 

http://chibnik.com/wp-content/uploads/2013/09/L6BatterySmall.jpg

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Turns out I lied.  The Variax battery box does contact that third contact on the battery.  Not sure what it does.  I will try to make some measurements.  From the above pix it does look like the contacts are slightly different.  Maybe the third element is used differently.  (The charger does not contact the third element)  I will make some meter measurements on my battery and see if I can see what is on the third element.

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OK I measured my Line6 JTV battery.  The third terminal is connected to the Negatiave (-) terminal with about 9.5K ohms.  It reads 9.5K in both directions so it's probably just a resistor - no diode.  My fully charged battery reads about 8.3V (4 LED's on the Variax test button)  Maybe rchibnik could compare readings on his Line6 and Mavica battery.

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My fully charged Line6 battery measures 8.45v on the two terminals, and 8.35 when I connect the negative to the third terminal

When I do the same thing on the Mavica I get 8.30v on the two terminals, but 0.01v when connecting the negative to the third terminal.

 

So my conclusion from those observations is that the Mavica lacks the terminal connection with the resistor. Next step would be to dissasemble the battery, followed by a small explosion. Let me get through my gig this afternoon, and we'll see about it tonight. Open to any suggestions.

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Did you try to measure resistance between the third terminal and the negative terminal?  Thats where I was seeing the 9.5K resistor.  The Battery itself is compatable.  Same voltage and capacity.  Measure voltage between third terminal and negative first.  IF it's zero, then try measuring ohms.  Don't measure ohms if there is any voltage reading at all between the third terminal and the negative.  You can try that on the Line6 battery too. You should see about 9.5K ohms between the negative terminal and the third terminal.

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My fully charged Line6 battery measures 8.45v on the two terminals, and 8.35 when I connect the negative to the third terminal

When I do the same thing on the Mavica I get 8.30v on the two terminals, but 0.01v when connecting the negative to the third terminal.

 

I would not recommend strapping that third terminal directly to either side of the battery. 

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Did you try to measure resistance between the third terminal and the negative terminal?  

 

On the Mavica battery, 

Placing the Red (positive) probe of the meter on the negative battery pole and the black probe on the third pole it measures -8.63 with the multi meter set to OMH 20K

Reversing the two probes (red on third pole, black on negative) shows 0.

Measuring across the positive and third pole yeilds nothing.

 

My line6 battery shows +11.1 so there appears to be a significant difference in how the third pole is wired to the negative pole.

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My comment was addressed to 'rchibnik', not you :-).  I'd hate to see someone let the magic smoke out of their meter.  My Fluke bench unit is quite tolerant of such abuse, but I doubt the low-end units are as well protected.

 

I am also seeing that quiescent 9.5K reading on the Line6 battery.  If UPS ever manages to get my JTV-69 back to me, I'll dig in and try to figure out whether that's really just a simple R between those terminals or, as I more suspect, the port impedence of some sort of crypto based protection system (typical of camcorder packs, toner cartridges, etc.). 

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Since I don't have another battery to compare I really can't say what is different between the Camcorder battery and the Line6 one.  I read it in both polarities to see if there was any sign of something other than a resistor in that circuit.  Doesn't seem to be.  If I had one of those cheap replacement batteries I would take it apart and see what's in there.  I like doing a little reverse engineering from time to time.  In the past I have been paid big bucks to do just that. :-)

 

I am not all that motivated to have a second JTV battery at the moment.  I would like to convert my Variax 500 to a better battery though.  I am using NIMH AA cells in it.

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I have been searching around and one possible use for the third connection is to monitor battery temperature.  Many Lithium batteries have an internal temperature sensor.  However, I would think this would come into play when charging the battery not when discharging it. 

I am so glad I started this discussion about less expensive battery alternatives. It is so interesting!! I love forums with smart people as members.

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Charlie, I bet you can find a round crimp-on terminal that will make a decent fit in the +/- contacts of the battery.  With a little hand tool work, you can probably fix them into a small piece of plexi and whip up your own connector. 

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I could do that but it would be hard to make anything that would be easy to insert and remove the battery.  I would probably hard wire it and make a way to charge it while still in the guitar.  I have a bunch of Lithium batteries for my electric model airplanes that have molex connectors on them.  That would be an easier route.  If I could find a Battery box like the JTV has I would use that but I doubt that anybody sells anything like that.

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  • 4 months later...

Charlie_Watt. Here is the battery box for the JTVs (I think): http://www.fullcompass.com/product/445858.html

Line 6 support told me full compass is where I should go for some things.

To add to this discussion (several months later): the pictures of the battery compartment here indicate all 3 contacts are in use, and go to a small PCB that has enough circuitry to indicate the 3rd pin is of strict importance.

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  • 1 year later...

FWIW, I played a 500 for many years, and although it was the perfect utility guitar for me, the power issues were a major PITA, so I finally got rid of it in 2014. The battery issue was this; the guitar was only reliable when using good quality carbon AA's but went through them so fast I would unplug the guitar during breaks to preserve them. I got two additional battery cassettes and kept one backup near the stage at all times. In an attempt to save cost i tried NiCAD's, but High MAH NICAD'S didn't have as much starting current when fully charged and lasted maybe an hour. There's nothing quite as frustrating as having the guitar start that damned "blinking on and off" during the solo I waited all night to play. Anyway, those issues have kept me away from the JTV guitars but, to my own amazement, today i will be trading something for a nearly new JTV 59S. I am experiencing guarded excitement about having another Variax, and more than anything else, I hope the battery it uses does become a problem.

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The card that came with the charger says that, in the beginning of the charge cycle, the red status light on the charger will be solid red. When the charge cycle is complete it will slowly blink, BUT leave the battery on charge an additional 60 minutes. Then, if you don't remove the battery from the charger, the charger with automatically go into a 20MAH trickle charge. I have tried this and it is correct. 

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  • 2 years later...

hi. do you guys have a link to a battery charger for the JTV? i lost mine in the fire. i just need a cheap chinese knockoff. the one from line 6 will cost me close to $100 here in canada. i think that is just way too expensive for a battery charger. please and thank you. you can email me at markdagul@yahoo.ca

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No cheap alternatives.

Log a support ticket in your account.

what is logging a support ticket will do? i have written a support ticket to line 6 about this problem 2-3 years ago and i have not received any response from them. until now, still nothing. this company has the worst customer support ever. just wanting something cheap to replace the one i lost.

i lost everything in the fire including the 3 extra batteries, the charger, the interface that connects the Guitar to the computer with a wire that looks like an "ethernet cable. i cannot even upgrade the firmware of the guitar or use any of the guitar's "on-board digital guitar/tunings". i am basically just using the pickups of the guitar,

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