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JTV69 Mag PU output terribly weak.

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My JTV69 with stock PU's has suddenly developed a problem.  The modelling works normal but the magnetic pickups are suddenly VERY low output.  All of the mags.  When I say low output, I don't mean a little low.  They're unworkably low.  You can still hear them but they're barely working.

 

Tried both the VDI and the 1/4 jack with same result.  Battery in or out, verified charged, same result.

 

It's just over a year old and has been working fine until last week.

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i'd open the back cover and trem and check for string fragments... sounds like something could be shorting out...

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i've seen the pictures above before.. don't know if that's the issue here... just something worth looking at!

 

What the ..... How did they get in there?
Nice call Zap, how did you know that?

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i've seen the pictures above before.. don't know if that's the issue here... just something worth looking at!

 

I always make sure the ends come out if a string breaks. Did they ever fix this issue? Didn't they put like a cable washer thing in later versions?

 

I have a late 2013, am I ok? I'd rather not void the warranty just by opening the back like that guy did in the photos.

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Thanks for the pics but I've got the guitar apart and can't find any string parts or any wires chaffed or undone connections.  I won't be able to put the guitar back together until Friday so I'll take a look at it then.

 

I'm guessing, from the symptoms, that it's something in the 5 way or the vol or tone pot.  Just a guess though.

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Who said you could not open the back?  I did that the first day I got mine to see what it looked like.  No I don't think they eliminated the path from the trem to the board.  They want those wires floating so that they don't interfere with the trem action anyway.  I don't have a problem with string breakage.  Can't remember the last time I broke one.

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Who said you could not open the back?  I did that the first day I got mine to see what it looked like.  No I don't think they eliminated the path from the trem to the board.  They want those wires floating so that they don't interfere with the trem action anyway.  I don't have a problem with string breakage.  Can't remember the last time I broke one.

 

Nobody said you can't open the back...perhaps my response wasn't clear. It's a ridiculous assumption...what he's basing it on, I have no idea. 

 

Not to mention utterly unenforceable, even if he's right. So what would be the point?

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It would have been more straight forward to say - it's ok to open the back.

 

Never mind...so noted.

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Nobody said you can't open the back...perhaps my response wasn't clear. It's a ridiculous assumption...what he's basing it on, I have no idea. 

 

Not to mention utterly unenforceable, even if he's right. So what would be the point?

 

I would imagine opening the back and doing something would risk voiding the warranty?

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"Voiding the warranty just by opening the back like that guy did in the photos" isn't "doing" anything. It's loosening a bunch of screws and removing a piece of plastic. Even plucking out the ball end of a broken string isn't modifying anything. Beating the innards with a ball peen hammer, or deciding to rinse the guts with turpentine would be "doing something". You're allowed to look at your own guitar.

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"Voiding the warranty just by opening the back like that guy did in the photos" isn't "doing" anything. It's loosening a bunch of screws and removing a piece of plastic. Even plucking out the ball end of a broken string isn't modifying anything. Beating the innards with a ball peen hammer, or deciding to rinse the guts with turpentine would be "doing something". You're allowed to look at your own guitar.

 

Ok.

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I always have the urge to take things apart to see how they look inside. :-)  Like the first thing I do when I look at a car is look under the hood.  I am careful not to break things.  I had all the covers off my JTV the first weekend after I got it.

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I took the bottom back cover off my 69 when I first got it because I heard something rattling around inside. I opened and found a loose bolt. I photoed it and sent pics to Rich when he was in charge and he said it belonged nowhere in the guitar, apparently a box of screws dumped on the work bench during assembly.

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Back on topic.

 

When I had the guitar apart all I did was look around and make sure the connections looked solid.  Anything that looked like it plugged into a circuit board I made sure it was seated firmly but didn't disconnect anything.

 

So now that she's back in one piece it seems to be mostly working fine except for cutting out sporadically.  I haven't spent too much time diagnosing that as it might be as simple as a bad cable but I'll give it a good workout to see if I can re-create it.

 

I didn't find anything inside my axe that shouldn't have been there but obviously something was wrong. 

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Back on topic.

 

When I had the guitar apart all I did was look around and make sure the connections looked solid.  Anything that looked like it plugged into a circuit board I made sure it was seated firmly but didn't disconnect anything.

 

So now that she's back in one piece it seems to be mostly working fine except for cutting out sporadically.  I haven't spent too much time diagnosing that as it might be as simple as a bad cable but I'll give it a good workout to see if I can re-create it.

 

I didn't find anything inside my axe that shouldn't have been there but obviously something was wrong. 

 

Have you considered sending it in to Line 6?

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Have you considered sending it in to Line 6?

Yes...I have.  

 

But that block comes later in the flowchart.

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Yes...I have.  

 

But that block comes later in the flowchart.

 

All I have to say is don't try to fix something you can have trouble with so you don't end up having to spend more money to fix more stuff on the guitar.

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If it sometimes works, you have either a bad cable or a bad connection somewhere.  Those problems can be hard to find.  You can send it in and they send it back saying NPF (No Problem Found).  When it's weak is it weak in all pickup positions?  If so, then it's not the 5 way switch.  The good news is that the circuit for the mags is very simple and same as a regular guitar when you have the battery out of your JTV.

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If it sometimes works, you have either a bad cable or a bad connection somewhere.  Those problems can be hard to find.  You can send it in and they send it back saying NPF (No Problem Found).  When it's weak is it weak in all pickup positions?  If so, then it's not the 5 way switch.  The good news is that the circuit for the mags is very simple and same as a regular guitar when you have the battery out of your JTV.

 

So a NPF can just be Line 6 being lazy and not being able to even find the problem theirselves? I was hoping they'd only do that when they concluded that there is no problem with the guitar at all, but if they're listening to a guitar with pickups not working and saying "Oh this guitar is normal" then wtf?

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I have this same problem now on my JTV59.  All 3 magnetic pickups are barely putting out sound.  Same results connecting with an instrument cable.  First of all, has anyone besides the thread starter experienced this?  Was there a solution apart from sending to Line 6.  I have a tour coming up and don't know that they could turn it around in time.

 

Thanks, all

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Had to give the 1/4 in output jack on my JTV69 a thorough cleaning to fix the low mag output problem. Wet the end of a 1/4 in plug with contact cleaner and insert/ remove it 10 times then do it again. I think I did it three times total.No problems for two weeks of heavy live gigging.  

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Good call Zap.

Happens once in a blue moon. Also can be a contact in the 5-Way switch.

 

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I've got the same problem, checked for string fragments,  don't know what else to try. I loved the sound of the mags!

Any help would be greatly appreciated

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I am having this problem with one of my JTV69s now. Checked the back cavities to make sure no broken string ends were in there. Checked connections were tight. Problem still exists.

 

I spoke to the nearest Line 6 repair tech by phone. He said the preamp may have failed. Does anyone know about the magnetic pickups on these using a preamp? Before I open up the fr4ont cavity, I'd appreciate any ideas on what to look for?

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Don't pull the pick guard. 

 

-Are the volume and tone pots loose? 

 

-Have you been doing any custom patches in Workbench? 

 

-Download any 3rd party custom patches? 

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UPDATE: I went through the entire guitar today with a multimeter. All connections and the wiring harness were good. Since I didn't have a copy of the schematic, I had no way to adequately test the main PCB-A. BUT...I do have another, identical guitar. So I swapped the PCB-A board out of the other guitar and PRESTO! everything worked fine. I called the service center tech again and reported my findings. I inquired as to what would be involved with getting a new one to which he replied, "Sounds like you're pretty handy with this kind of thing - why don't you call Line6, order the part and do it yourself?"

 

So I called Line6 and they were extremely helpful. They said they had not heard about this happening (so I referred them to this thread). They told me how to proceed.

 

So if anyone else out there experiences this, you want to order the "PCB-A Main Guitar+G11," part #50-02-0320-2 from Full Compass.

 

They also suggested re-flashing the firmware before ordering the part...

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" So if anyone else out there experiences this, you want to order the "PCB-A Main Guitar+G11," part #50-02-0320-2 from Full Compass. "--- that doesn't always work

for all boards. The afore mentioned query list is a starting point for troubleshooting. And that part number only applies to JTV-69/69S, special order thru FC.

 

Your older one may have a different firmware revision in it, so it will sound different than your later serial number guitar.

 

Not advisable to do self repair, as these are not passive electronic guitars. There's more to these than meets the eye.

Got to cuddle this cat under the chin a little differently.

 

 

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UPDATE 2: Flashing the firmware fixed the problem!

 

Who would have thought that the firmware would fix the MAG pickups?!

 

PSARKISSIAN: Both of my JTV's are out of warranty. Both are about the same age. I am the Minister of Music for a local church and use one JTV-69 as a backup for the other. I keep all the firmware, patches and sound sets in in sync at all times. Before these, I owned a Variax 500 that I heavily modified and giggled with for nearly a decade.

 

I worked as an audio engineer/producer from 1989 - 2014 - I have been trouble shooting and repairing instruments and studio gear for a long time. An old Line6 tech I knew used to work on my V500 and allowed me to observe his work when several parts failed at different times (including a bridge cable and 2 piezo bridge sadles). 

 

I do thank you for clarifying that the part# is explicitly for certain JTV-69 models. :)

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" Who would have thought that the firmware would fix the MAG pickups?! "--- being the guy that works on these,

I would. But that's only because I've seen this before a couple of times and know what to expect. These are a little

different than the Variax of old, and that tech was probably my lab mate. :)

 

Glad you didn't pull the pick guard, many do and regret getting in too deep, then it ends up on my bench. That occurs

all too often.   :(

 

Glad I and my colleague in Support could help. Now make some music.  :)

 

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lol... and here I sat, racking my brain, trying to figure out how you managed to poke everything with a multimeter through the pick guard. I was starting to get a headache. ;)

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