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Removing components from switch and pot lugs?

MuseChaser

MuseChaser

Super Member
I could use a few tips from those with more experience than me. I'm in the process of going through a Dynaco SCA80Q that I built back in the middle-to-late 1970s at the age of 15 or so, with the help of some excellent supplies, tips, and support from Dan Joffe at updatemydynaco.com. Have repopulated all of the capacitors on the power amp boards, done a FULL repopulation of both preamp boards, and replaced all of the large capacitors, input jacks, binding posts, etc., all with Dan's parts and it's been lots of fun. (I've also built his Akitika PR-102, and I could rave about that product, his design, and Dan himself forever, but that's for another thread). Suffice it to say that, by now, I'm comfortable using desoldering wick, a solder sucker, and working with small components on PC boards. Wish I had the skills I have now (not that they're unusually good by any means) back when I built this Dynaco!!

Which brings me to my question. When I built it, I took the Dynaco instructions to heart, insuring a "good mechanical connection" between each lug-mounted component and switch or pot by wrapping and crimping the leads around the lug prior to soldering. Great. Except that they are now a BEAR to remove without damaging the switch lug. I've replaced the caps on the power switch and the resistor on the mode switch so far, but came close to ruining the mode switch. The lugs to which the resistor are mounted are now loose and wiggle a bit, but the switch tests OK at each position fortunately.

Before proceeding further, I wondered if anyone has any advice as to how to deal with this. Too much heat...too much force unwinding leads... I could snip the old components off, leaving their leads in place, and solder to the leads I guess, but...well... sloppy?

Thanks in advance, and all the best.

Barry
 
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Yes it's always been a dilemma. When trying to salvage, best I could do is heat as little as possible, suck up as much as solder as possible and use needle nose pliers to pry the wires off of the tabs, hoping the wires were made of copper and not steel.

Now with this in mind whenever I solder something I don't do "good mechanical connection" in hopes that I don't have to fight this when it comes time to take it apart...as long as it wasn't intended to come apart someday...
 
audiodummy said:
...

Now with this in mind whenever I solder something I don't do "good mechanical connection" in hopes that I don't have to fight this when it comes time to take it apart......
Click to expand...

That's the approach I'm currently taking; make sure everything is clean, good contact, and a good solder joint, but all with the idea that, at some point, I may wish/have to remove it! Thanks for the input.. appreciated.
 
I always have issues with this- especially when I want to reuse the components. I use clip-on heat sinks whenever I can, and try to be "delicate" when bending leads around. But yea, it can be a real pain in the butt, and it frequently takes WAY more time than I had anticipated when it comes to completely striping & cleaning something as simple as a rotary switch.

And don't even get me started on never seeming to be able to get the light exactly where I want it in a chassis.
 
If you’re replacing a component, it is often wiser to clip it out, then desolder the piece of lead left in the lug. Especially on rotary switch lugs. Shorter application of heat, too. It is absolutely permissible to use the old parts leads to put a new part in place, whenever it makes more sense, due to accessibility issues, fragility of the lug, or areas that heat will damage.
 
Another thing is if you find yourself unsuccessful at separating everything after several seconds of heating... stop, let it cool down, look at why, and try again. Also don't be afraid to add solder/flux to desolder... yes it's wasting solder but if you can get it done faster, the better.
 
MuseChaser said:
Thanks very much for the replies and suggestions. I guess there's some small comfort in knowing I'm not alone in finding this portion of repair/renovation work to be less enjoyable. Misery loves company.
Click to expand...
This is something that I’ve always had trouble with, and I would imagine that 99% of others have had the same trouble. I’ve got a lifetime of experience, as a hobbyist and professional. Sometimes, what you have to do ain’t pretty, but in the end, if it works, don’t fix it!
 
I would clip the leads, then using sharp cutters try to cut through the solder blob/wrapped wire so when heated, you can just remove the smaller pieces, not have to unwrap wires. I'd try to shear it down relatively close to the potentiometer tab.
 
It depends on what you’re trying to do. When I’m replacing a can cap I want to save the wire length for reinstalling later. Then you can’t just cut stuff off. Suck solder, bend leads, pry, hope, repeat until done.
 
Thanks again, everyone, for the tips. That part of the job is done, finally. Clipping the components out, then working with just the remaining leads was a big help. Also, when possible, pulling the switch itself with everything still attached, even if it could only move half an inch or so, sometimes gave better angles. In three cases, the entire switch or pot came out so I could do a good job getting the lugs nice and clean for the new components. Some other things I learned...

1. At least for me, a spring-loaded solder-sucker did more harm than good. The recoil smashed and loosened a couple lugs, but the switches, thankfully, still tested and functioned properly.
2. Solder wick works very well.
3. Higher heat for shorter periods of time is much better. I started out at 340C, trying to be careful, but found that 375C worked a LOT better, faster, and did less damage.
 
Solder sucker has always worked great for me. I use it, then reheat the joint and pry the wrapped wire loose with a pick (straight version of dentist's pick). Wiggle the part and it'll stay free. Too hard to get the wires off after clipping.
 
Which solder sucker are you using? I went through a few random cheap ones and could never get em to work very well. And then I got a Soldapullt and it's great. I clean/scrape it out after every few pulls to minimize back-spray. This was not a paid endorsement.
 
I can also atrest to the fact that cheap solder suckers don't work half as good as a genuine soldapult solder sucker. Most of em are big and blue and have a yellow bumper on the plunger.
I've got 2 of em around here...

Rather than waste perfectly good new solder "wetting" a joint, just to suck it, take a minute to understand what's going on.
The solder you're using contains flux, that's why adding some causes the joint to flow immediately. Unfortunately, in order to access that flux you need to use the lead that its infused in.
Flux is nothing more than refined pine sap, rosin. Its easy to get, cheap and the environmental cost is almost nothing.
Lead on the other hand is expensive, toxic heavy and hard to find, it's also an environmental nightmare.
So, what I'm proposing is don't keep adding that expensive solder to a joint that's going to come apart anyway, because once it's off the roll it's not ever useful again...
Get yourself a small dropper bottle with some rosin, cut in alcohol, and flux your joints. The flux acts like grease in a frying pan to transfer heat to the joint, but it also is a mild acid whe warm. The acidity cleans the corrosion and oxidation from the parts while at the same time carying heat.

If you do it right the flux turns brittle like glass and flakes off into a fine dust.
Often times when working on old equipment you'll find the remaining flux still stuck to the terminals. Flux is your friend, it's not really something a person should try and solder without...
Save the solder (last pound I bought was about $80 for genuine Kester.)
Use the flux ( I spent a day generating a coffee can full of rosin that will be my soldering flux, sufficient for the rest of my life.)
The pine sap works as good as any commercial product available and smells far better than all of em.
 
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True I can't believe how much solder has gone up in price, not sure why. But I still think adding solder sometimes help not just because of the rosin, but rather it's a bit more thermal mass to keep things liquid so you can have a bit more time before things solidify.

That being said I wish I can reuse the waste solder I've collected over the years, would be nice if I could make wire out of the solder again. Alas this used solder is full of contaminants and probably won't stick well anymore, not to mention the mix ratio is unknown after mixing all sorts of solders together...
 
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