Tone POT not functioning as it used to: UPDATE

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rparker
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Tone POT not functioning as it used to: UPDATE

Post by rparker » October 9th, 2011, 11:30 pm

It's on my Ibanez ART-100 that I got 18 months ago and subsequently put so,e GFS P90s on it. It's got a 3-way toggle and a 2-vol, 1-tone config. Adjusting my tone with the tone knob does almost nothing. It just happened within the past week or so, as I was playing it recently without issue.

Would it likely be a POT, or perhaps I did something wrong when soldering over a year ago and it's developed a short of some sort? My plan of action is to make sure there doesn't look like any shorts in it and then replace the POT if it all looks good. maybe I cooked it when I replaced pickups last year or something. the only other thought would be the CAP. Are these more likely to go bad, or less likely? I'm not opposed to replaceing one. They're cheap, and perhaps the stock one that came with the humbuckers may not be optimal for the P90s anyway?

Anyhow, I appreaciate any thoughts. I'm planning to replace the POT at least, and maybe the CAP if there's one better suited for the P90s than what's in there. (which I don't know right this moment)

Anything else you folks think I should think of?
Last edited by rparker on October 11th, 2011, 1:16 pm, edited 2 times in total.
Roy

"I wonder if a composer ever intentionally composed a piece that was physically impossible to play and stuck it away to be found years later after his death, knowing it would forever drive perfectionist musicians crazy." - George Carlin

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Re: Toe POT not functioning as it used to

Post by TRGuitar » October 10th, 2011, 5:52 am

I would think it would have to be the pot or cap. Something shorting out maybe taking the tone pot out or the circuit? :?
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Re: Tone POT not functioning as it used to

Post by rparker » October 10th, 2011, 12:26 pm

My ability to have no simple repair is staggering. I just ran it through the positions and all scenarios and one thing is certain. It's a huge mess.

Toggle Up:
tone does not work
Neck P/Up works, but only clear in loudest position. Maybe last 10%. Very muffled below that.

toggle mid:
both pickups work if POT on
tone has minimal effect on bridge p/up and no effect on neck pickup
bridge and neck pickups behave similar, meaning the top 10% thing volume wise.
bridge POT off, neck POT on has output. Bridge on, neck off. NO output, like with Les Pauls. (turn neck about 1/4 on and there's tone just like with LPs.)
Bridge vol POT way up, neck vol POT 20% on and the tone POT works just fine. Do opposite and tone POT has almost no effect.

Toggle bottom position:
Tone POT 100%, bridge and neck p-ups both off = as loud as if bridge volume position was at 50% or more. turn tone off and it's total silence, as expected.
neck vol POT off, bridge vol pot 75%, tone zeroed = no volume
neck vol POT off, bridge vol pot 100%, tone zeroed = volume
neck vol POT off, bridge vol pot 100%, tone any level = volume, with tone at what you'd expect for it's setting.

This thing is messed up. It wasn't recently. These scenarios make no sense unless I accept that the center-piece for this clustermess is the tone POT and it's just doing whacky things. Having said that, I there's a chance for a faulty switch. Hmmmmm I'm pretty sure I have the spare POT and CAP. I'll probably start there. tomorrow. :)
Roy

"I wonder if a composer ever intentionally composed a piece that was physically impossible to play and stuck it away to be found years later after his death, knowing it would forever drive perfectionist musicians crazy." - George Carlin

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Re: Tone POT not functioning as it used to

Post by Blue Jay » October 10th, 2011, 12:35 pm

Hey guys. Yes, it sounds like a pot or the cap that goes with it. Heat hurts both. You can try a new cap first by twisting it around the leads of the old one, as there are no high voltages inside. Of you could temporarily solder another pot into the same circuit and try that, but if it works, you will be pulling out the old pot anyhow, undoing the nut on the shaft and all that jazz.

Ohh, and in the interest of showing an educational and enlightening variety, here's really good deals on polypropylene (chiclet style) Orange Drop capacitors as well as Angela, tin foil in a can? Umm... they have paper in oils too, but they are anywhere from $5 a pair to $20 each and that is a bit much. But, I haven't seen this supplier's name come up here yet. 8)

http://angela.com/sbeorangedropsscranda ... itors.aspx

At the end of this, I see your last post Roy :shock: , and what seems like a myriad of problems. Yeah, change the pot and cap first. And you are right to suspect the switch now too, but leave that till later.
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Re: Tone POT not functioning as it used to

Post by rparker » October 10th, 2011, 3:01 pm

Well, my bag o parts only coughs up some full size 500K POTs (taper ad linear) and some orange ceramic CAPs like these at Guitar Fetish. http://store.guitarfetish.com/Ceramic-D ... p_151.html

My guitar has much smaller looking POTs, but no idea the specs. Covered in solder, and the Ibanez Web site is showing the diagram for a year earlier, acive instead of passive pickups and 50k pots as a result.

It's also got some sort of bigger cap on it. I'm running P90's instead of the stock humbuckers, so I'm not sure that I even need to stick with those big, flat things. Sorry, I can't even see the writing at this point. the Ibanez site's non-matching diagram does show the approx size and shape of the CAP. http://www.ibanez.com/supportResources/ ... RT2008.pdf Blue Jay, I don't see anything on that site you pointed to that's like it and Googling this thing hasn't produced anything of value. Notice in the pdf that the cap has the #s 104 right above it.

So, Will the full size POT work? It appears that I have the space. Do the POTs all have to be the same ohm or whatever the rating is? I've got enough here to replace the lot if I need to do so.
Roy

"I wonder if a composer ever intentionally composed a piece that was physically impossible to play and stuck it away to be found years later after his death, knowing it would forever drive perfectionist musicians crazy." - George Carlin

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Re: Tone POT not functioning as it used to

Post by Blue Jay » October 10th, 2011, 4:54 pm

Sure, a full size pot is usually better quality, and the good names are Alpha and CTS. Roy, those little pots are quite easy to fry, they simply don't take as much heat - it's a matter of their surface area and mass etc. The element, or wiper, inside can get fried or worn out from use, as well. Different ratings are okay, you can make a case for using either 250K ohm, or 500, but 250 is more common with bright single coils. It tones them down a bit for some reason, but I have used 500K and 1 meg ohm for louder applications. For the tone however, try to stick with the linear pots and leave audio taper for volume.

Ceramic caps are fine, except they are sensitive also and can crack from heat, as well as handling. I've crumbled a few. I'll try to find a diagram on http://www.guitarelectronics.com, but will send this off now. :)

Okay, so here is a general diagram, for 2 humbuckers and your configuration. I know you have P90's which can be visualized with this layout. Good luck. Let us know what's happenin'.

http://www.guitarelectronics.com/produc ... -Tone.html
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Re: Tone POT not functioning as it used to

Post by rparker » October 10th, 2011, 5:28 pm

I think I'll give the full size POT a try tomorrow. I'll do a temp connection of some sort to see if the cap is good or not. I'll stick with the old one if I can. One less thing to change the tone. I liked the way this one sounded until recently. If I get really ambitious, I'll try them both and see which one I prefer.

Thanks, Blue Jay, for all the ontel and the links. 8) 8)
Roy

"I wonder if a composer ever intentionally composed a piece that was physically impossible to play and stuck it away to be found years later after his death, knowing it would forever drive perfectionist musicians crazy." - George Carlin

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Re: Tone POT not functioning as it used to - UPDATE

Post by rparker » October 11th, 2011, 1:15 pm

'Oy! The solder on there must be something that takes 1000 fires to get to it's liquid state. I now have a very clear understanding how it could have over heated. I replaced the tone POT and the CAP with one each of the items I discussed yesterday. works mighty fine....to a point. There is more than one defect.

The tone pot functions well for both pickups, but it does channel volume on it's own still. there's also that crazyness about the mid-position toggle behavior where the neck will put out volume no matter what the bridge pup vol knob is set to, but not visa versa. Just looking at the other two, I am willing to bet that both of the remaining POTS could be questionable.

I remember having to borrow some solder once. I wonder if this was the time and if the solder was not the right type for the job. regardless, I think it's time to print out a diagram, look deep inside myself and decide if I want to tackle this right now. My soldering handy is NOT steady in the very least.

BUT, I do have functionality as needed and it sounds great. worse comes to worse, I let it fly like it is and replace the next POT that goes bad and so on and so forth. doesn't sound too appetizin when I put it that way, does it?
Roy

"I wonder if a composer ever intentionally composed a piece that was physically impossible to play and stuck it away to be found years later after his death, knowing it would forever drive perfectionist musicians crazy." - George Carlin

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Re: Tone POT not functioning as it used to: UPDATE

Post by Blue Jay » October 11th, 2011, 1:35 pm

Allright, kudos and congratulations for the effort, keep up the hard work, or enjoy it already, yes? Sounds good enough. :)
Like a bird on the wire,
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Re: Tone POT not functioning as it used to: UPDATE

Post by rparker » October 11th, 2011, 2:48 pm

Nah, I decided to go on and do the bridge vol POT. That fixed everything else. Functions as designs. The Neck POT did not look like it had received near the heat that the other two did. I left it alone. The tone of the ceramic CAP sounds just fine going through the BDRI. I'm quite satisfied and quite done. 8) 8)

Thanks for your help and especially that last wiring diagram. It gave me piece of mind that I was at least putting it back together properly. It actually was connected properly all the way around. Bad POT. It's a bad thing on many levels. :mrgreen: :mrgreen:
Roy

"I wonder if a composer ever intentionally composed a piece that was physically impossible to play and stuck it away to be found years later after his death, knowing it would forever drive perfectionist musicians crazy." - George Carlin

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Re: Tone POT not functioning as it used to: UPDATE

Post by Blue Jay » October 11th, 2011, 4:41 pm

Oh WOW that's good news Roy. It must be very satisfying to have it all working, fixed by you. I'm happy for you, play on! :D
Like a bird on the wire,
like a drunk in a midnight choir
I have tried in my way to be free.

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Re: Tone POT not functioning as it used to: UPDATE

Post by Artisan Luthiers » May 5th, 2019, 7:44 am

First, check your solder connections. They can be bad even if they are "physically" connected. If the solder is not chrome-like shiny (appears dull gray) you may need to redo the solder work.

For more information, you may want to see this blog article on understanding guitar pots and caps, which includes links to other relevant articles from top guitar related websites.
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