Reliable Slide Switches?

This does not supprise me. Switches designed for switching a faire amount of power do not work very well on low power or "dry" circuits. Your LED's are essentally such a circuit. You probably cannot find a slide switch that is designed for "dry" circuits. Even if you did the next person that comes along might replace the LED's with the original halogen bulbs and burn out the switch. No solution just info. CP

** That is utterly wrong !!!!!!!!

The circuit is still 12V and the load is several watts - so NOTHING like "dry switching".

** Also completely wrong - most slide switches are just fine for the job.

So called "dry switching" applies to signals like audio and video where the level is in the millivolt range and perfect contact must be made with no signal at the time of switching.

The OP's hunch is likely close to the fact and he only needs to DO a post mortem to find out.

.... Phil

If you can detach the power supply, try running the switch with a 120V incandescent lamp as its load (60W to 100W bulb). It's possible some small amount of oil or dirt is coating the switch, and 100 mA isn't enough current to burn it off. The polymers in a switch, or grease that makes it slide, can outgas or seep into the metal/metal contact area with distressing results. That switch is supposed to handle higher voltages and currents, and might be self-cleaning if given a chance.

I've always felt that "Reliable Slide Switch" was an oxymoron.

Allodoxaphobia wrote in news:slrno3dudp.2g4q.knock_yourself snipped-for-privacy@vps.jonz.net:

Perhaps, but I'd be surprised if I have more than a few hundred cycles on these things. That's rediculous.

Doug White

whit3rd wrote in news: snipped-for-privacy@googlegroups.com:

I've tried cycling them to wipe off any thin flim or corrosion. It feels more like a mechnical problem than anything else. If I flip it & it doesn't light, I can often get it working by backing up the switch just a hair & wiggling it. Getting it working at one point during the day is no guarantee that it will work the next tiem I try it an hour later.

The particular switch (C&K S102031SS03Q) has a plastic body, which surprised me. I may try at least seeing if I can find an old fashioned one with a metal housing.

I'd love to find one with threaded holes in the mounting ears. That would be a lot easier to work with.

Doug White

It IS a mechanical problem, if the film on the metal is too tenacious to be dislodged by sliding. You haven't any control over the contact pressure, but you CAN increase the electrical stress, and carbonize the insulator as you run the switch over it (creating a hot spark).

You can get slide switches with threaded holes. This is typically used in a ceiling fan.

"Ron D." wrote in news: snipped-for-privacy@googlegroups.com:

I haven't found any with threads with the required 1.125" hole spacing.

I have found both a Switchcraft and a CW switch that use the old style folded metal & phenolic PCB construction, but no threaded holes. Both are rated for 3A (vs 6A for the plastic C&K), which should still be OK, even for the original 20W 12V AC halogen bulb. With the LED replacement bulb, it should be loafing.

Both the Switchcraft and the CW cost about half what the C&K do. They are all so cheap that I will probably just order a couple of each. I will try the C&K again on the theory that I may have gotten ones from a bad batch. I'll also take the flaky one apart & see if I can figure out what the failure mechanism is. if one of the replacements dies prematurely, I will install a Switchcraft.

I'll report back when I have the replacements in hand & do an autopsy on the bad one.

Doug White

Yes, I'm with you. I have seen some very special switches that had a slider or rocker that operated a microswitch with a cam-like mechanism. These were probably for aerospace reliability level applications, and prices accordingly.

The typical slide switches have really mediocre contacts with thin plating, and once the springy contact fingers had worn down, you'd get poor contact, base metal on base metal.

Jon

Maybe some ideas to consider if all else fails:

1. Is there enough thickness to cut a thread in the mounting hole with a fine-pitch screw tap? The data sheet shows it to be 0.052" (1.32mm).
2. Consider glueing a nut onto the switch with epoxy, although from the data sheet there is very little space between the hole and the body of the switch for a nut.
3. If you can get to the power lead to the lamp, consider fitting a separate, more reliable switch in the lead, and just leave the slide switch in the "on" position (or even solder a short circuit across it).

--

Jeff

Check out

(RVSS6) You may have to verify that they are threaded. It's been a while since I ordered that part. The switchcraft 46206 series doesn't have threads.

You can also use two of these speed nuts:

Too bad this place doesn't give dimensions. Here's

a place that does.

Just a random thought.

I had a small single bulb floor lamp I used over a music stand. The switch was inline with the cord, not a slide switch but a thumb wheel type.

I put a CFL in it. I got arcing when switching and the switch didn't alway s work. I had to go back to an incandescent. My take was that the electro nics in the CFL were too much for a maybe marginal switch. These run at a power factor less than 0.6. Anyway it worked fine with an incandescent.

And yet, now I have an LED in it and that also works fine.

Doug White wrote in news:XnsA6CCE394CADA1gwhitealummitedu@69.16.179.42:

Haven't had a chance to tear apart the old switch, but one of the CW brand switches Digikey sells has threaded holes (although it's VERY hard to tell from the data sheet), so that will make replacing it easier in the future. Also, it's a DPDT, so I can tie the contacts in parallel. That ought to extend the life at least a bit.

In the meantime, I tried to fix a dead rechargeable stick vacuum this morning, and the proprietary 3 position slide switch is toast. I suspect it got cooked from my daughter's hair clogging the beater brush & stalling the motor. It seemed like every time I went to use it the brush was seized up and I had to spend a half an hour pulling hair out. She's got her own place now, so that should be less of an issue in the future...

Doug White

Doug White wrote in news:XnsA6EA927AC720Bgwhitealummitedu@69.16.179.43:

I took apart the original switch that died. The construction inside is very different from the typical ones with a phenolic board. The C&K is molded plastic, and the contacts are to the side of the switch slider, rather than underneath. The contacts didn't look pitted or worn, but there was some green corrosion. The design looks like it should provide a good wiping action, but the force is supplied by a wimpy little coil spring. I suspect that the corrosion built up to the point where the feeble wiping force couldn't reliably break through the crud. I had tried sliding it back & forth to scrub the contacts, but that didn't do it. I don't know if the spring is too weak to start with, or maybe took a compression set over time.

The DPDT CW brand switch with the threaded holes installed very nicely, and with the contacts doubled up, it should last a long time. Not having to mess with pop rivets means it will be trivial to replace if I ever need to.

Thanks for all the input & discussion.

Doug White

Switchcraft / Conxall does mfg. Slide Switches with "Tapped Flanges" (available special order #2).

Switchcraft 46200 Series Slide Switches, 2 Position, 1 Pole, 2 Pole : Spec Sheet

Standard Slide switch (larger then 1.20"). 46200 Series are 2 Position, 1 Pole, 2 Pole

SPECIAL ORDER FEATURES

1. .344 inch (8.74 mm) high knobs are standard; other heights available.
2. #6-32 and #4-40 tapped flanges for mounting available).
3. P.C. terminals.
4. Series 46000R switches are CSA marked on special order only.

w9gb wrote in news: snipped-for-privacy@googlegroups.com:

The CW switches with the threaded holes I bought are very similar to Switchcaft's design, and have the same contact ratings. The big advantage of the CW's is that Digikey stocks them...

Doug White

ilable special order #2).

ec Sheet

Pole, 2 Pole

I keep thinking that touch-button (semiconductor), not push-button (mechani cally actuated) is what you want. Touch button means there's no mechanicall y actuated "turn on" or "turn off" parts to get worn out.

Touch button just stays there motionless when you touch it and maybe lights

-up or whatever, but it starts what you want without its own motion which c ould cause its own wear and tear. Buttons without wear and tear mechanical motion are offered by companies like "ideal", "little fuse", "keymatech", e tc ...