bought NOS leaf switches - why are the contacts blackened?

[rockin_rick]

I bought some leaf switches off of ebay and they were listed as "Top Quality New Old Stock" http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=150082893286.  When I got them, I noticed that the gold contacts were kinda "dirty" - there is greyish black corrosion.  Does this indicate that they have been used, and are thus not "new"?  Do the contacts on NOS leafs "get dirty" like this over time without use?  Should I be concerned about the "dirt"?  The "connectors" on the leafs show no signs of being used (no solder, no scratches like connectors had been on).

These are the first leaf switches that I have had or seen in person.  Do these look like NOS leafs?  Is there anything else about them that seems not right, perhaps they are cheap imports or something?

Basically, did I get duped by the seller?

Thanks,
Rick

[fatfingers]

All I know is my NOS leafs I bought looked way nicer than that.  That said, I'm sure those could be cleaned up and will still work nice.

Good luck.

[Fozzy The Bear]

When I got them, I noticed that the gold contacts were kinda "dirty" - there is greyish black corrosion.

Those are NOT Gold contacts..... Gold does not tarnish or corode at all. The contacts you have are standard leaf switch contacts that have (by the look of them) been brazed onto the copper leaf. You find this type in pinball machines quite a lot.

There's nothing wrong with them at all. This is quite normal. Get a small brass wire brush and give the contacts a brush up and they'll be fine. Then once you have your buttons in place you need to adjust the leaves by gentle pressure on them until they contact at the right time.  You'll find that you need to do this about every six months with traditional leaf switches.

The tarnishing is just due to age.... perfectly normal.  They don't look used at all. They've no scratch marks or solder on the wire attachment points. They've probably just been stored in a draw full of the things.... I know that's how I store them at work. The cosmetic condition isn't exactly important, because you never see them.

Best Regards,
Julian (Fozzy The Bear)

[Knievel]

I'd say they're NOS Wico parts, just looks like they oxidized over the years.

You only need to clean the small points where the leafs actually touch.
Very fine sandpaper or an emery board should make them like new again.

[Fozzy The Bear]

You only need to clean the small points where the leafs actually touch.
Very fine sandpaper or an emery board should make them like new again.

No No No!!! NEVER with sandpaper or emery board!!!! You wear away the contact surface that way. Only ever a light rub with small a Brass wire brush. You can get them from car parts dealers, they sell them for cleaning contact gaps on spark plugs. They look like a toothbrush with brass bristles.

Best Regards,
Julian (Fozzy The Bear)

[rockin_rick]

Thanks guys, I won't worry now.  The example shown was one of the more tarnished ones.  There were others that wern't so bad.

Thanks again,
Rick

[Knievel]

Sorry Foz, guess we posted at the same time.

No need to shout!! Yes the emery board would be overkill on these, was forgetting they were new. Most of the leafs I come across would never come clean with a brass brush.

I still feel the sandpaper would be a good idea. I have a 400 grit that use for these. It's barely more abrasive than regular paper but just enough to polish them. It's also much easier to fit between the leafs than a wire brush.

Good luck Rick.

[Fozzy The Bear]

No need to shout!! Yes the emery board would be overkill on these, was forgetting they were new. Most of the leafs I come across would never come clean with a brass brush.

Sorry dude! didn't mean to shout.... 

Best Regards,
Julian (Fozzy The Bear)

[RandyT]

Hmmm.  I always used to clean mine by pulling clean white paper through the contacts while pinching them together.  Just keep repeating until it stops leaving black streaks on the paper.

RandyT

[pointdablame]

Hmmm.  I always used to clean mine by pulling clean white paper through the contacts while pinching them together.  Just keep repeating until it stops leaving black streaks on the paper.

RandyT

That's exactly how I've cleaned mine in the past.  I tried a paper towel first but that's not a good idea.  Printer paper has worked fine for me.

I've never really cleaned leafs that were in really bad shape though.

[Kremmit]

Operators back in the day used to just whip out a business card and drag it through the contacts, just like Randy described with the paper.  You can wet the card with rubbing alcohol and it might get a little cleaner than without. 

I would definately not use anything very abrasive- even that wire brush sounds like too much, but maybe it's softer than I picture it.

[fjl]

You can use a scouring pad. Those scrape without scratching. A dry new one of course. Don't go using a beat up pad fresh from washing dishes.

[Level42]

I didn't use it for my leaf switches (I simply bought some brand new one's....) but whenever I need to clean copper/gold contacts (Like PCB edge connectors) for my work, I use a glassfibre brush.

I never use chemical contact cleaner sprays because they work for a short time, then make things worse than before !

It's cleaning very good and doesn't harm the copper/gold at all. You'll have to disassemble the leaf contacts to use it though, since the brush is in a pen shape.

This is what I mean:
http://www.3dstereo.com/viewmaster/sup-gfp.html

O, and don't try these on your fingers....I'm serious here, it hurts and particles of glassfibre may intrude your skin...