Glad you asked. Cleaning and what to lubricate are the fundamentals of pin repair. Basically one can cause long term heartbreak using rough techniques on contacts or the wrong substance in the wrong place. The silver contacts on most switches/relays are actually self cleaning. They benefit from being used. Even the black silver oxide is a good conductor. Use a business card drawn between them. We have not debated this here at PN but I think Deoxit contact cteaner may be the one product safe to use on pins. I have only used Deoxit on flickering bulbs. It has worked. I'm going to refer you to a past reply about this. Good luck and do click the link to PIN REPAIR.com...C_S
P.S.> I was re-reading the info below. It occurred to me that one might wonder why he refers to pinball contacts carrying HIGH Voltage. Most EM games have 24 volt for playfield coils. Some 70's machines +48V. In my book that's not high V's. The arcing comes from "Reverse EMF". It is a current returned to the circuit from the collapsing magnetic field around a coil. Reverse Electromotive Force runs up into hundreds of volts(+2/300V Why?...I don't know) It is called reverse cause the pulse has the opposite polarity of the applied voltage. Many later games have diodes wired across the coil to absorb those current spikes.
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01-27-2014, 05:12 PM
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Pinball Nirvana Forums - View Profile: Coil_Smoke@@AMEPARAM@@View Profile: Coil_Smoke</title>@@AMEPARAM@@Coil_Smoke
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Join Date: Dec 2011
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In The Begining
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The first thing I read about EM repairs was this game saving info regarding cleaning contacts and lubrication...C_S
1f. Getting Started: Lubrication
(Why Contact Cleaner & WD-40 are BAD.)[/SIZE]
- Lubrication in EM Games.
Electro-Mechanical machines, for the most part, do not use any lubrication. Most parts run "dry." Far more damage can be done to a machine by over-lubricating, than by under-lubricating. As a rule, if in doubt as to lubrication, don't do it! Throw that WD-40 away, it won't be needed here (besides, WD-40 is very flammable, and with EM switch arcs, it could start the game on fire!)
As a general rule, keep this in mind for EM moving parts: Metal to metal lube is OK. nylon to metal NO lube. Nylon to nylon NO lube. And NEVER EVER lubricate the moving metal plungers inside coils (even if the metal plunger is moving inside a metal coil sleeve). Also NEVER lubricate the gears of the score motor.
In regards to nylon, all reference I find from professional plastics companies speak of nylon as "no lubrication required." In fact they mention how nylon can be worn by various greases that collect dust and act as an abrasive paste. There is also a concern about nylon expanding when it it lubricated. This is just more evidence that you should not lubricate any nylon parts.
Generally the only parts that will require any lubrication are stepper moving "fingers" and some other metal-to-metal moving parts. There aren't very many in an EM game. So keep that lubrication in the tool box and away from the game. I tend to only use lubrication on stepper units and not much more than that. I used them on some 1950s score reels too (metal to metal) such as the pivot points for rotating arms.
When there is a need to lube an EM game, using the right lubricant is very important. Do not use white grease. Do not use WD-40. White grease solidifies and WD-40 gums up in a short amount of time. Do not use silicone-based lubricants either.
The only lubricant needed is Teflon based lube, or simple #10 oil, or Williams CoinOp Lube. Personally I like the Teflon Lube Gel. It's available from precisionreloading.com/superlube.htm and pinrestore.com as "Super Lube". Get the 3oz gel tube. This stuff is the best EM lubricant and the only EM lubricant you will need.
Contact Cleaner & WD-40 are BAD for EM Games.
WARNING: DO NOT USE CONTACT CLEANER OR WD-40 IN EM GAMES!
Sometimes first-timers will use contact cleaner on the switch contacts of an EM game (somehow they think a chemical will solve a mechanical problem!) DO NOT SPRAY EM GAMES *ANYWHERE* WITH CONTACT CLEANER! Spraying switch contacts with contact cleaner or WD-40 does some really bad things, AND IS EXTREMELY DANGEROUS. It is also guaranteed to make the game fail and not work as time progresses.
Contact cleaner is made for LOW VOLTAGE situations. Low voltage means +5 volts. EM games are HIGH VOLTAGE. Contact cleaner is *not* designed for high voltage, and does *nothing* to fix or clean a high voltage switch! Contact cleaner was designed for gold or tin low voltage (+5 volts) switch contacts, not the silver or tungsten high voltage contacts used in EM games. Again don't try and use a chemical to solve a mechanical problem.
Also contact cleaner and WD-40 are *extremely* flammable. I have seen people spray it in a game, turn the game on, and the game burst into flames! Because of the high voltage and the switch arc, the contact cleaner explodes into a ball of fire. Typically this will start the cotton cloth wire insulators on fire too, rendering the game unrepairable. (After the fire is put out!) All that is left is bare wire with no insulation.
Often the over usage of these spray materials get into the bakelite switch spacers, the wire insulation, and the plywood around the switches (the bakelite switch spacers can shrink with contact cleaner, changing the gapping of the switches too.) This provides a constant source of the spray product, and causes even more problems down the road. After the user thinks it's all clear to turn the game on, BOMB it bursts into flame (again!)
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The Coin unit on the bottom panel of an EM Gottlieb that was sprayed with
contact cleaner. The game started a fire, burning all the wiring and the Coin unit
itself! This is just ONE reason why you don't want to use contact cleaner.
If this is going to be fixed, ALL the burnt cloth-covered wire in this area will
need to be replaced. Also the bakelite plates on the Coin unit will also probably
need to be replaced too, because they will be very brittle.
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- [FONT=verdana,arial,helv,helvetica][SIZE=-1] Also, contact cleaner in the presence of an electrical arc (which is seen on all high voltage EM switch contacts), causes a chemical reaction. This reaction produces phosgene gas ([/SIZE][/FONT]<tt>COCl<sub>2</sub></tt>[FONT=verdana,arial,helv,helvetica][SIZE=-1]) and free chlorine. The free chlorine attacks the silver EM switch contacts and makes silver chloride (an insulator). The game now has this white, insulating material on the switch contacts! Once this happens, the switches will not work. It's like putting a piece of tape between the switch contacts. Silver chloride (an insulator) is completely different than silver oxide, which is a conductor. Silver oxide is the black dust normally seen on switch contacts (the black dust is not necessarily a bad thing).
There is no reason to use a chemical for a mechanical problem. Dirty and mis-adjusted switches is a mechanical issue. Don't solve this type of problem with a chemical.
If you insist of having to "clean" out your game, the best I can offer you is to do it this way: Take the entire bottom panel out of the game, and bring it outside. Stand it on end and use some compressed air to blow off the dirt and crud. That's as far as you should go when "spraying" the switch contacts on a game. I know a guy that takes each part off the bottom panel and puts it in an electrosonic cleaner. That works too, but it's a lot of work, and it's certainly not worth all the trouble in my eye.
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