keeping socketed parts in place

[mr.adambeck]

Hey I made a fuzz for someone who is leaving for tour soon.  After shows, their pedals get thrown in a box, which then get's thrown in the back of a van, which then proceeds to drive on bumpy highways.     
I'm worried that in the hustle and bustle the transistors in her fuzz pedal could fall out of their sockets.  Is there anything I can do to be sure they are stuck there for good?  Thanks!

[anchovie]

Solder the legs into the sockets!

[hday]

A tiny drop of hot glue to one of the leads might be a slightly less permanent solution. Tape is also an option. Making sure the leads fit snug without forcing themselves back out is probably the best choice. I sometimes sand the leads lightly until they fit well in the socket, but choosing a socket that doesn't force the transistor leads out, like those metal grabby ones sometimes do, can make transistors less likely to jump out.

[Nitefly182]

Remove the sockets and solder the transistors in place. Other than ICs, socketed parts aren't the best bet for poorly treated touring gear.

[mth5044]

Remove the sockets and solder the transistors in place. Other than ICs, socketed parts aren't the best bet for poorly treated touring gear.

This.

Or just cover the board in hot glue   

[davent]

Maybe a piece of foam/sponge/weatherstripping  that will press firmly against the board and components when the back is put onto the enclosure.

dave

[R.G.]

I have what is probably an heretical view on sockets. This comes from my long term association with electronic devices and the accumulated lack of awe that long association brings in most cases.

There are times when only a socket will do, as in sorting/matching JFETs or germanium, or programming chips, or when a specific chip is so expensive that you can't take a chance on removing it, or when removing a chip is destructive to the board. But sockets are mechanical contacts. They are *inherently* unreliable as compared to a soldered joint. Sockets, like any mechanical device, vary in the degree to which they approach perfection, but none of them reach it. If they are used long enough, every socket contact *will* some day fail.

So I'm with the "solder them into the socket" answer, or better yet, do all your socketed selection first, then solder the parts into the board without a socket at all. Use diagonal cutters to remove ICs or transistors from PCBs.

I decide up front whether I can afford to destroy the device I would otherwise socket. If the answer is no, I will use a socket. If the answer is yes, I don't. I am biased heavily to not using sockets. I acquired scars learning this.

[mr.adambeck]

I guess my concern with not using sockets is frying some transistors.  Are there other precautions I can take to make sure I don't?  Also - can I just use any type of glue on there?  IE - Can I just buy a hot glue gun and go at it?

Thanks!

[Mick Bailey]

Use a small crocodile clip on the lead as a heat sink and solder the transistors in. My old radios that have germanium transistors are all soldered in - In fact I'm listening right now to a GEC portable from 1961 with soldered-in transistors. I've never seen any commercial gear with socketed transistors (though I'm certain that someone has). They would be unreliable in the longer-term and add extra cost to the manufacturing process.

I even wonder whether any consideration was given in the early days to heat sinking during soldering. A lot of radios were hand soldered by semi-skilled operators who used massive soldering bits by today's standards. Much of the kit still in use has proved to have a lifespan way beyond what could have been imagined at the time.

It would be an interesting experiment to see just how much heat would be necessary to destroy or severely affect a transistor.

Gluing in transistors is a medium-term approach. Eventually the leads will oxidise and cause the circuit to malfunction and the glue can also contribute to failure due to chemical changes in the glue over time, or reactive components already within the glue.

Where I have stuck components I use a Bostick hot-melt gun, but this is only for repair work where a component was originally glued - mainly electrolytic capacitors glued in for mechanical strength.

[mr.adambeck]

Thanks for the alligator clip tip!  That was one of those smack your head and go "duh!" moments...  Can't believe I never thought of that! 

[mr.adambeck]

Also, what is this "goop" stuff that people keep talking about?  What is it, and does it oxidize as well?  Do pedal builders purely use it for covering up what they did from DIYers or does it actually help keep the circuit together?

[Top Top]

I don't think this is the best solution, but one thing I noticed is that if you squeeze the leads of a diode or transistor with a needle nose pliers, it leaves treads/indents in the leads, which then grip better in sockets.

[Taylor]

Also, what is this "goop" stuff that people keep talking about?  What is it, and does it oxidize as well?  Do pedal builders purely use it for covering up what they did from DIYers or does it actually help keep the circuit together?

Pedal builders purely use it for covering up what they did from DIYers.

I'm not sure what specific material they use - would be a funny subversion to reverse-engineer a boutiquer's gooping scheme.

[R.G.]

I guess my concern with not using sockets is frying some transistors. 

OK. That helps.

(1) Get better at soldering. Yes, I know that's easy to say, hard to do. But it's kinda like skiing - if you're not falling, you're not trying hard enough. Or the alternative quip - life is like a bicycle; if you're coasting, you're going downhill. Use a well tinned, hot iron, good rosin core solder, and *heat the PCB pad first* until it runs the solder like water, then touch the transistor lead.
(2) Don't worry about overheating parts other than germanium transistors. If your soldering technique is decent, you have no problems.

OK, this is going to sound crazy, but stay with me. I regularly use the cut-off leads of resistors as jumpers and temporary terminals for testing. I can tin the end of a 1" resistor lead while holding the other end with my thumb and index finger and not burn myself. It gets hot, but not to the point where I can't get the tinning done.

I'm not a masochist by any means. That means that I let go of things at about 130F/55C. So a soldering iron tip about 1" away from my fingers has time to make a decent coating of solder on a wire before the heat can conduct to my fingers. This can only happen if the soldering iron is good and hot and well tinned. The cooler the iron is, and the poorer the heat transfer from the iron, the longer it takes to get the soldered point hot and the more time the heat has to get to the "cool" end.

When you can do this little trick, you can solder any silicon anything and not overheat it. In fact, I just solder germaniums with no special care. A heat sink clip is a good idea, and the standard "soldering kit" from Radio Shack used to have little aluminum clips for exactly that.

Like any skill, the watchword is practice. Then more practice. Then more practice. How long did it take you to play a clean, decent sounding "F" chord?

[Paul Marossy]

Use diagonal cutters to remove ICs or transistors from PCBs

When I mod pedals for people, I sometimes have to replace the existing IC chip(s). If it's a single sided PCB, I can usually just desolder it without damaging anything.

But the double sided PCBs pretty much mandate that I have to cut the device off the PCB and then desolder each pin that remains until they are all removed so I can put a new device in. It's my opinion that if you build a kit or something with a double sided PCB that you should use sockets, because it's a real PITR to get them off the PCB otherwise.

I also socket transistors. I'm not personally concerned with them falling out as the sockets do a good job of holding them in. But, if I'm really concerned about it, I'll use foam or something to put pressure against it so that it absolutely can't happen.

[petemoore]

  I trust 'em too Paul, have been having 100% performance...AFAICT..So far, no troubles.
  Shaping the transistor leads first, to be cut short, makes the center of force very near the socket lugs [less leverage when the transistor gets 'bonked sideways'].
  Complex shape...not really, the outside leads need to go out in a mild diagonal, then point straight down [sort of an S shape], then, after shaping, cutting the 3 leads flat across their bottoms makes a good short solid fit.
  If you cut and then shape, the middle lead will be longer and the transistor rocks side to side, all 3 lugs can't seat completely.
  Seated low like that, you'd have to really smash on your boxes to get one out without grabbing and pulling.
  AFAs soldering them in, high heat and especially 'attractive' copper pads [cleaning, polishing...whatever works for you] allows the solder to work much more quickly and 'take' to the copper, if you have to burn off a layer of oil or whatever from the pad first, chances are the 'oil' in the transistor will also boil before the solder takes. A ~hot, freshly cleaned/tinned tip and clean pad go a long way to making the soldering process not turn into a 'hafta burn through it' situation.

[JDoyle]

I've used nail polish and non-acetone remover. Don't know how good of an idea that is though - but I don't use sockets, save for BBD chips and anything else I don't want to put an iron to - and that doesn't include transistors.

[aron]

I usually solder the components to the socket.