Is it possible to damage a Vol pot with too much heat?...UPDATE

[tcarp]

I have a '69 Thinline RI with 250K pots and stock pickups. Yesterday I took an SD nech mini humbucker from my partscaster....it worked just fine in another guitar....and swapped it into the Thinline.

It's a simple 3 way switch and wiring with the braid soldered to the Vol pot. This is the same configuration that was in my partscaster. The stock Thinline bridge remains. While I had the controls exposed I added a drop of solder to any loose connections.

When I plugged it in, neither pick up worked. I tried several amp cables to no avail.

I've had it apart three times and have checked and rechecked for loose joints. On advice from another forum member, it was possible that the braided ground wire may have made contact with the switch or other connection so I wrapped it in electrical tape.....still no luck. The braid was pretty gnarly looking so I soldered a jumper wire from the braid to the pot. Still nothing.

The only thing I can think of is that I damaged the volume. Both Thinline pickups were working before the mini bucker swap, as did the minibucker and bridge pup in the partscaster.

I'm stumped. I have no equiptment to test electronics. I've done simple swaps before and never a problem.

Any Clues?

Thanks

Tom

UPDATE 5/13

After re-aligning the finnigan pin, shaving a few mils off the thermo-throckel coupling, and replacing the dilithium crystal, I found success.

I had the contols out at least 5 time in the last two days. I assumed I fried the vol pot, so I finally replaced the entire control assembly with a spare I had laying around for another project. I ended up with the same problem.

Then it hit me....unlike a conventional Tele control assy where there's a ton of room and nothing gets in the way, the Thinline controls are more compressed. I had to bend/turn the tone pot so that the shaft lined up with the hole on the pick guard. I didn't break any connections, but a connection came in contact with the capacitor lead and caused a dead short. That was the problem all along. I simply placed a small piece of electrical tape between connections and that solved the problem.

Whle I was under the hood, I eliminated a loud buzz I had gotten previously by running another ground from the bridge to the tone pot....got rid of about 50% of the noise.

I'm using 250K pots and the mini humbucker sounds a little dark, but not unlistenable. When I had the same configuration in a solid alder partscaster the mini hum was fairly bright....must be the semi-hollow nature of the Mahogany Thinline. But I'm not complaining.

Thanks to all for the advice.

Tom

[voodoostation]

It is quite possible to fry your potentiometer with a soldering iron, more than a few here have done it. Highly recommend you pick up a multimeter. If you're only using it for your guitar and voltages no higher than household, you can find them for 20 dollars or less. Handy to have.
Now, are you getting anything? Buzz, hum, noise when you tap the pickups with a screwdriver? Any crackling sound when you turn the pot/pots?

[banjohabit]

yes you can damage a pot with excess heat. also, if you are gonna do this stuff you may as well get yourself a multimeter. they are inexpensive time-savers and frustration preventers. it would be kinda nice to KNOW what is going on in your guitar about now, would it not ?

[dsutton24]

There's a wire that runs from the switch to the volume pot, disconnect it from the volume pot. There's another wire that runs from the output jack to the middle lug of the volume pot, disconnect it from the volume pot. Tie the two disconnected wires together, and see if you have sound. If so, something's wrong with the volume / tone circuit. If you don't have sound, it's the cable, jack, switch, pickups or intervening wiring.

What you're basically doing here is wiring the pickups directly to the jack, bypassing the volume and tone controls. It's possible to troubleshoot without a meter, you just divide and conquer.

[alnicopu]

Yes, I fried a pot the first time I ever replaced a set of pickups. I kept reheating the back of the pot to try and get a good joint. Constantly reheating will warp the inerds to where it will hardly move or make good contact.

Adding a drop of solder will not make a good joint. It takes enough heat on both surfaces for the solder to flow when added. Also, tin both surfaces before soldering them together. Its never a good idea to just add a drop of solder by putting a bit in the solder tip then holding it to the surfaces in hopes it will stick. I'm making an assumption here that this is what you did.

Another thing. Throw away any electrical (vinyl) tape you have lying around. After a couple of years the sticky stuff used on it will turn to a tarry goo and the vinyl will become hard a brittle with age. I always use shrink tubing.

[JuSteve]

When I have to solder on the bottom can for a ground, I pry open the 4 tabs and remove the guts before soldering.
Yes, I fried a few pots.

[MickM]

You almost have to try to damage a pot while soldering wire to it. Until recently buying this highly recommended video,http://terrydownsmusic.com/solder_vi...ldervideo.html and getting a decent soldering station, I wired guitars with big primitive guns with the headlight etc. and never over heated a pot.

If you just clean up the back of the pot with sandpaper or emery cloth and slather on some flux you'll have those pre tinned grounds layin' in a silver puddle in no time.

In the linked video Terry wires a Tele and explains in detail every step. Wish I had it 30 years ago! And I have zero financial interest.

[Bud Veazey]

I didn't think it was possible to fry a pot until i did. I knew the big Weller solder gun was too big, but I got away with using it by being careful, but one careless moment fried that pot. After that I invested in a real soldering station. As someone already said, if you're using the right equipment, it is very hard to fry a pot.

[Mreilander]

Soldering to pots requires HIGH heat and speed. This allows you to get the solder on quickly, instead of slowly heating the pot. I have damaged many pots in the past with too low a heat, or bad tips with carbon build up.

-Tin the tip
- Apply tip to back of pot
-apply solder to pot and wire (not the tip)
- as soon as the solder melt to the pot, remove the heat.

the process should take no longer than a second or 2

[Mreilander]

Put a meter on the center pin and the outer pin. It should give a you a variable resistance reading when turning the knob.

[Tuxedo Poly]

CTS and Bourns pots are less prone to heat damage than some others.
You have to be quick, the recommended max soldering time is 3 seconds at 260°C.

[JohnS]

Originally Posted by Mreilander

Soldering to pots requires HIGH heat and speed. This allows you to get the solder on quickly, instead of slowly heating the pot. I have damaged many pots in the past with too low a heat, or bad tips with carbon build up.

-Tin the tip
- Apply tip to back of pot
-apply solder to pot and wire (not the tip)
- as soon as the solder melt to the pot, remove the heat.

the process should take no longer than a second or 2

+1. I use a 25 watt iron for wiring and a 100 watt for pot backs.

[editorjuno]

Originally Posted by JohnS

+1. I use a 25 watt iron for wiring and a 100 watt for pot backs.

I use a 25-watter with a small chisel-shaped tip for everything, although a 35-40 watt iron would be even better. The things to keep in mind regarding soldering to pots imo are as follows:

1. Do not reuse an existing large solder blob -- unnecessary and risky.

2. Use small solder blobs, one per lead.*

3. Apply the new small solder blob first, twist and tin the stripped lead end, re-tin the tip, reheat the new blob, then when it reflows insert the stripped, twisted, and tinned lead end into the molten blob and immediately pull the tip away.

This procedure eliminates the need to use a high-wattage gun or iron and works every time.

* Got this idea from Bill Lawrence

[slowpinky]

Great thread! - it seems harder to fry the CTS and Bourns pots - but using a cheap 25 watt gun I trashed a lot of cheaper and mini pots before finally getting a solder station (these arent that pricey nowadays) - but great advice here for 'all thumbs DIYers like me!"
cheers!

[voodoostation]

Glad you got her straight Tom, them little things like to bite you every chance they get.

[jefrs]

If you use a bigger iron, which provide more heat (not more temperature) then you can be on and off the pot can before the whole lot gets hot and you fry the pot
A 15-25W iron is not man for the job, you need to step up to around 40W.

Imo best tool is a 45W Weller TCP (temperature controlled pencil), which can do the fine work of a small iron but has the heat capacity of a big one.

[editorjuno]

Originally Posted by jefrs

If you use a bigger iron, which provide more heat (not more temperature) then you can be on and off the pot can before the whole lot gets hot and you fry the pot
A 15-25W iron is not man for the job, you need to step up to around 40W.

Imo best tool is a 45W Weller TCP (temperature controlled pencil), which can do the fine work of a small iron but has the heat capacity of a big one.

Such an important point -- higher wattage and higher tip temperature are two different specifications. A higher wattage iron isn't necessarily hotter, it's just capable of heating up a larger object!

[banjohabit]

Originally Posted by editorjuno

I use a 25-watter with a small chisel-shaped tip for everything, although a 35-40 watt iron would be even better. The things to keep in mind regarding soldering to pots imo are as follows:

1. Do not reuse an existing large solder blob -- unnecessary and risky.

2. Use small solder blobs, one per lead.*

3. Apply the new small solder blob first, twist and tin the stripped lead end, re-tin the tip, reheat the new blob, then when it reflows insert the stripped, twisted, and tinned lead end into the molten blob and immediately pull the tip away.

This procedure eliminates the need to use a high-wattage gun or iron and works every
* Got this idea from Bill Lawrence

you do realise that this is in direct conflict with the soldering axiom that i grew up with : "the bigger the blob, the better the job." ?

[editorjuno]

Originally Posted by banjohabit

you do realise that this is in direct conflict with the soldering axiom that i grew up with : "the bigger the blob, the better the job." ?

Never heard that one -- but I did learn to solder during the late 1950s, when we were all taught that it was "proper practice" to establish a strong mechanical connection by wrapping the stripped/tinned end around the terminal before soldering, advice that iirc was in every Heathkit, Dynaco, and Eico kit manual back then. Imagine my surprise when I opened up an electric guitar for the first time and found all those ground lead ends just stuck into a big solder blob on the back of the volume pot, something that would have voided the warranty on all those kits I built back in the day -- IOW, there's often a difference between so-called "proper practice" and how things actually get done efficiently in the real world.

[dhuber]

I've never thought of removing the metal can around the pot, Great Idea. I use a Weller 20 or 25 W Iron on my leads. However when attaching my grounds to the can I hit it with the 250W gun and solder flows like water. I guess I've been lucky.