X-Wing PCB mounted switches... Am I nuts or??

[Dirk_Hendrik]

I've gor a repair job to do for a pedal of which at least one of the 2 footswitchs is unreliable. These are the 2pdt x-wing type but the PCB mounted version. Straight wires, no solder holes.... No problem with that.... I thought till half an hour ago.
Wherever I check they seem to be gone.. The smallbears, banzais etc ets.
Anyone got a tip?

[Mark Hammer]

Don't take it as gospel, but my experience with these switches is that malfunctions often arise from heat-related reflow of the small dab of grease used to seat the rocker contact in its pocket within the switch.  If too much heat is applid during soldering, the grease can end up coating the contacts and impeding signal flow.

If you are able to gently lift the side tabs from the switch, you can remove the plunger mechanism, revealing the innards.  Take the rocker contacts out, clean the likely coating of grease on them with alchohol or whatnot, clean out the inside of the pockets with a Q-tip, and reseat the rocker contacts.  Then repackage the switch by pinching the tabs.  I like to put a small dab of Stabilant contact enhancer on the contact before reinsertion but this is not critical/necessary.

I have "rehabilitated" a number of such switches by this means, and they haven't failed me after that.  Note that the grease itself is not necessary for switch functioning.  Rather, it is used to temporarily hold the rocker contacts in place while the switch is being assembled from the top and bottom halves.  The few seconds it saves for the manufacturer means something to their bottom line, but means nothing in our context, which is why we can simply clean it up and carry on.

[snoof]

i've had bad luck recently w/these switches.  my voodoo labs microvibe switch, and a brand new switch from small bear, both failed last month .  thanks for the heads-up on your repair trick, i'kk have to give it a shot...

[Mark Hammer]

Again, I'm not promising this is the source of ALL stompswitch difficulties, but I've found it to frequently be the source of mine.  From a user perspective, of course you can only see what the application of heat is doing on the outside of the switch, and not what it might be doing on the inside.  People might think that if the plastic hasn't melted yet that everything is hunky dory....when it isn't.

It is possible to avoid this sort of problem during assembly by strategically heat-sinking or heat-isolating the switch lugs.  The general idea is that you first establish that the internal rocker contact is NOT in electrical/physical contact with the lug you are presently soldering.  So, check the continuity of the lugs with your meter.  If the common is not in contact with a given side lug, then it is OK to solder that side lug and its same-side partner.  Now, press the switch so that contact with the other set of side lugs is lifted, and solder those 2 (or 3 as the case may be).  This still leaves the two/three commons in the middle.  Wait until the side lugs have all cooled down, and take your best shot at soldering the commons quickly.  In a perfect world, that should result in minimum heat build-up and minimum grease reflow.

That does not eliminate the possibility that the switch in general is a stinker, but it will reduce the likelihood that an industrial lubricant will coat the internal contacts and become the source of intermittent continuity.

[Dirk_Hendrik]

Thanks Mark!
I'll give it a try. The malfunctioning you describe is exactly what I have here!

[analogmike]

Again, I'm not promising this is the source of ALL stompswitch difficulties, but I've found it to frequently be the source of mine.   If the common is not in contact with a given side lug, then it is OK to solder that side lug and its same-side partner.  Now, press the switch so that contact with the other set of side lugs is lifted, and solder those 2 (or 3 as the case may be).  This still leaves the two/three commons in the middle.  Wait until the side lugs have all cooled down, and take your best shot at soldering the commons quickly.  In a perfect world, that should result in minimum heat build-up and minimum grease reflow.

pure genius!!!!!!!!!!!

[calculating_infinity]

Hey Mark,
    Thanks for the tip, when my X-Wings mess up (oh you know they will), I'll try it out!

-Jonathan

[Mark Hammer]

Now that I am given to think about it, perhaps the negative impression people have about X-wings is precisely because they have such big solder lugs, relative to the 3PDT types.  The larger lug size means that more heat from the soldering tip is sinked away from the joint, hence more heat is required for a longer period to produce what people feel is a reasonable joint.  What this means is that because of the "large target", there is greater risk of reflow of the grease UNLESS steps are taken to keep the heat away from the rocker contacts.

In essence, what I am saying is that the X-wings by themselves are decent switches, and not "doomed" in any strict sense.  But, because the grease is used to temporarily seat the rocker contacts, these switches in particular play into our worst tendencies and invite greater risk of malfunction because of that.

I wonder if it is possible to persuade the manufacturer to produce them without the grease?  The switches would probably cost a little more, but it would be worth it, I think.