Dot Studio Tone Pot and Ground Problem

[EpiEric]

A few days ago I was playing my Dot Studio unplugged (one of my favorites to play after the kiddos go to bed) and noticed that the tone knob was wobbly. I turned the knob and realized that the pot was pretty much just free spinning in the hole. I used the two spoons trick to pull the knob, retightened the nut underneath the shaft, replaced the knob and didn't really think much more about it.

 

Yesterday, I went to play it plugged in and the formerly very quit guitar now has serious 60 cycle hum and it will "pop" when you touch the bridge with one finger when you're not touching the strings.

 

If I hold the strings with one hand and touch the output jack with the other, it's silent. So, I assume it is some kind of ground problem. In addition to this, the tone control now doesn't do anything.

 

When the pot was loose in the socket did I break a solder joint that could have removed the tone pot from the circuit and somehow also broken the ground?

[Whitmore Willy]

If I hold the strings with one hand and touch the output jack with the other, it's silent. So, I assume it is some kind of ground problem. In addition to this, the tone control now doesn't do anything.

 

When the pot was loose in the socket did I break a solder joint that could have removed the tone pot from the circuit and somehow also broken the ground?

 

Not being a wise guy but, that would be my guess.

 

Willy

[bigneil]

yup, sounds like the ground has come off the tone pot. if you have a soldering iron it's easy to just pop the wire back on again.

[Whitmore Willy]

One other thought....

On some Epis in some years, the harnessing was connected together with a small plastic plug.

I have a L.P. that was that way before I changed it. When it was new I had a similar problem. When I fiddled with the connector the problem disappeared.

 

Willy

[EpiEric]

yup, sounds like the ground has come off the tone pot. if you have a soldering iron it's easy to just pop the wire back on again.

 

In a hollowbody like the Dot Studio, do you happen to know what the pot is typically grounded to? Is it grounded to the jack socket? Or elsewhere?

 

Does anyone know if there's enough wire in there to pull the tone pot through the F hole without breaking any other joints?

[wiggy]

In a hollowbody like the Dot Studio, do you happen to know what the pot is typically grounded to? Is it grounded to the jack socket? Or elsewhere?

 

Does anyone know if there's enough wire in there to pull the tone pot through the F hole without breaking any other joints?

 

Having recently had mine apart I can confirm it's grounded to the jack (actually everything grounds to the earth tab on the switch and then to the jack)

 

Yes you can.

[EpiEric]

Having recently had mine apart I can confirm it's grounded to the jack (actually everything grounds to the earth tab on the switch and then to the jack)

 

Yes you can.

 

 

Thanks, Wiggy. Very helpful info.

[wiggy]

Thanks, Wiggy. Very helpful info.

 

If you can bear with me til tomorrow I'll dig out a 3D wiring diag for the Dot Studio which really helps

[animalfarm]

If you can bear with me til tomorrow I'll dig out a 3D wiring diag for the Dot Studio which really helps

 

Now THAT'S something I would LOVE to SEE!

[wiggy]

Now THAT'S something I would LOVE to SEE!

 

OK - It's 3D as in the sense of being a 3 dimensional drawing rather than a 2D schematic so no special glasses required.

 

Would look pretty cool though I agree

[Whitmore Willy]

OK - It's 3D as in the sense of being a 3 dimensional drawing rather than a 2D schematic so no special glasses required.

Would look pretty cool though I agree

And I was ready to make a killing selling these guys glasses!

 

 

Except for her....She still can't figure out how to put them on.

 

Willy

[EpiEric]

I found the Dot Studio wiring on the Gibson site:

 

http://www.gibson.com/Files/schematics/Dot%20Studio%20wiring.pdf

 

So anyone have any guesses as to which connections are broken?

 

Or is the best bet to just pull out all the wiring?

 

If I remove the output jack completely, what's the best way of being able to get it back in place? Are there any tricks to threading that needle?

[animalfarm]

The answer(s) to your questions MAY be found Here:

 

From EPI Lounge DIY thread, Guitar "Projects" section:

 

"ES-335/SEMI HOLLOWBODY Electronics Removal and Installation"

http://www.mylespaul.com/forums/tonefreaks/40089-335-electronics-installation-k-how-take-years-off-your-life.html

[Whitmore Willy]

EpiEric,

 

This may or may not help. If nothing else it may provide some hints:

 

 

Also, if you do a search on youtube there is an entire series (several parts) by RS Guitarworks. Has a lot of good info. It also takes much longer to watch as they redo all the electronics. Do the search for replacing pots in 335.

 

One last thought...If you can tie the strings to the parts before you pull them out you do not have to fish the strings through afterwords. Tie the string to the part before completely removing the nut.

 

Also for the record...Everyone has their own way but (when necessary) I prefer to enlarge holes by hand!

 

Willy

[EpiEric]

Animalfarm and Whitmore Willy, that is very helpful info.

 

So is there any way to tie a string to the input jack before pulling it? I can see how the washer works for getting it back through, but in the case of removing the jack, once you've unscrewed the nut I guess you just have to fish it out?

[Whitmore Willy]

Eric,

 

OK...couple of thoughts. (might work, might not)

If the jack has the nut on a full nuts width, you may be able to just loosen it enough to tie a thread on it before completely removing the nut. After pulling it through, you could tie a string onto the thread and then pull the string through.

 

Second thought... In the video I like the washer idea. What it doesn't show you is the guy cutting the string after he puts the nut on. Consequently, it also does not show him turning the guitar upside down and shaking the daylights out of it to get the washer out of the guitar. (like a long lost pick)

Maybe it would be a good idea to tie a string to both sides of the washer.

 

Willy

[jerrymac]

A few days ago I was playing my Dot Studio unplugged (one of my favorites to play after the kiddos go to bed) and noticed that the tone knob was wobbly. I turned the knob and realized that the pot was pretty much just free spinning in the hole. I used the two spoons trick to pull the knob, retightened the nut underneath the shaft, replaced the knob and didn't really think much more about it.

 

Yesterday, I went to play it plugged in and the formerly very quit guitar now has serious 60 cycle hum and it will "pop" when you touch the bridge with one finger when you're not touching the strings.

 

If I hold the strings with one hand and touch the output jack with the other, it's silent. So, I assume it is some kind of ground problem. In addition to this, the tone control now doesn't do anything.

 

When the pot was loose in the socket did I break a solder joint that could have removed the tone pot from the circuit and somehow also broken the ground?

 

Try this before you start pulling the electronics out - take a piece of wire and connect the shafts of the two pots. That should fix the problem if the tone pot lost ground connection. Or connect the shaft of the bad pot to the nut on the jack. This way you confirm that's it's a ground problem before ripping out the electronics. If it works, you can even just get a thin piece of bell wire and run it from the pot & the jack (under the nuts) and save yourself a bit of work.

[Whitmore Willy]

Try this before you start pulling the electronics out - take a piece of wire and connect the shafts of the two pots. That should fix the problem if the tone pot lost ground connection. Or connect the shaft of the bad pot to the nut on the jack. This way you confirm that's it's a ground problem before ripping out the electronics. If it works, you can even just get a thin piece of bell wire and run it from the pot & the jack (under the nuts) and save yourself a bit of work.

Jerry,

Great tip.

A copy is going directly to my notebook.

 

Willy

[EpiEric]

Ack! Of course I didn't see JerryMac's advice until getting myself in a little deeper on this. Things have finally slowed down enough that I got to take a look at things. I still am not clear on what is missing in the wiring. Even looking at the diagram I am a little confused.

 

Here is what I have:

 

This is the tone pot - has one black wire (can't see where this one is connecting other than here currently) a capacitor, and the blue wire (white inside the insulation) that connects to the volume pot:

 

 

Here is the volume pot - Blue wire connects to tone pot, red wire I assume is the hot pickup wire, then there's the gray wire that connects to the output jack.

 

 

Here's a shot of the volumne and tone together. You can see where the blue wire connects the two and the gray wire that runs to the jack.

 

 

Here's the jack itself - it just has the one gray wire that connects to two of the lugs on the jack itself and to the volume pot:

 

 

So what connection am I missing that's causing it to be ungrounded? If I hold the jack and the shaft of the tone pot at the same time, it's perfectly silent. I know there should be a wire that connects between both pots and the jack, but I'm not sure if it's the gray wire or the black wire. And if it's the gray wire, i'm not sure why the tone pot is the ungrounded one if the black wire isn't connected to the vol. pot.

 

Thanks for all of your help, my Epiphone genius friends!

[jerrymac]

Ack! Of course I didn't see JerryMac's advice until getting myself in a little deeper on this. Things have finally slowed down enough that I got to take a look at things. I still am not clear on what is missing in the wiring. Even looking at the diagram I am a little confused.

 

Here is what I have:

 

This is the tone pot - has one black wire (can't see where this one is connecting other than here currently) a capacitor, and the blue wire (white inside the insulation) that connects to the volume pot:

 

 

Here is the volume pot - Blue wire connects to tone pot, red wire I assume is the hot pickup wire, then there's the gray wire that connects to the output jack.

 

 

Here's a shot of the volumne and tone together. You can see where the blue wire connects the two and the gray wire that runs to the jack.

 

Here's the jack itself - it just has the one gray wire that connects to two of the lugs on the jack itself and to the volume pot:

 

So what connection am I missing that's causing it to be ungrounded? If I hold the jack and the shaft of the tone pot at the same time, it's perfectly silent. I know there should be a wire that connects between both pots and the jack, but I'm not sure if it's the gray wire or the black wire. And if it's the gray wire, i'm not sure why the tone pot is the ungrounded one if the black wire isn't connected to the vol. pot.

 

Thanks for all of your help, my Epiphone genius friends!

 

Looks like the tone control is not grounded. I'm betting that the black wire on the tone control goes to the bridge. If you look where the capacitor is soldered to the back of the tone pot, it looks like there was a wire that broke off, probably the shield from the blue wire coming from the volume. You can strip some of the blue covering to expose the shield wire and attach it to the back of the tone pot.

[EpiEric]

Jerry, thanks for the quick reply!

 

Pardon my density here, but do you mean just strip part of the blue down to the bare wire and then solder it to the back of the tone pot?

 

That wire itself is pretty short and I am not sure I can solder it in a way it will not pull apart when I pull the pots back into place. Was that the wire that was originally soldered there? I don't see any bare spots on it's length.

 

What would happen if per your earlier suggestion I just soldered a piece of wire to the backs of the two pots? Would any particular gauge of wire be preferable? Would that complete the ground?

 

Or are there more more correct options since her guts are already out?

[jerrymac]

Jerry, thanks for the quick reply!

 

Pardon my density here, but do you mean just strip part of the blue down to the bare wire and then solder it to the back of the tone pot?

 

That wire itself is pretty short and I am not sure I can solder it in a way it will not pull apart when I pull the pots back into place. Was that the wire that was originally soldered there? I don't see any bare spots on it's length.

 

What would happen if per your earlier suggestion I just soldered a piece of wire to the backs of the two pots? Would any particular gauge of wire be preferable? Would that complete the ground?

 

Or are there more more correct options since her guts are already out?

 

The blue wire is called shielded wire and consist of 2 parts, the white wire and a shield wire that looks like braided mesh. If you carefully strip away the blue covering you'll see the braided wire, and that's what was connected to the back of the pot. If you look at where the blue covering, you can see some remaining mesh wire where it broke off. If you can imagine it, that blue covering was originally sitting on top of the tone pot.

 

You're right about it breaking off when you try to put everything back in place. But don't worry about it, just connect a wire to the back of the two pots and everything will be fine. Use Goldilocks wire, not too thick, not to thin... Like the black wire that's on the tone control now. Leave a little slack just in case you have to maneuver them a bit when you're putting it back together, and test everything thoroughly before you put the electronics back in!!!

 

Good luck!!!

[EpiEric]

Success!

 

Jerrymac, I took your advice and I soldered a piece of wire between the two pots and that completed the ground. Pulled everything back into place and she is all good to go again.

 

Thanks to you and everyone else who offered tips and advice on this thread.

 

This is why I favor this forum - can't beat the people.

 

Thank you!