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Author Topic: Cleaning Relay Contacts?  (Read 2944 times)
KB2Z
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Posts: 7




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« on: December 27, 2002, 09:28:27 PM »

Could anyone suggest a better way to clean delicate relay contacts?
I have tried a jewelers file and contact cleaner spray.
They both worked for a short time.
The problem persists and I dont want to cause anymore wear on the contacts.
The problem relay is RL-101 in a Tempo One if one could be found?
Thanks in advance,
George KB2Z
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K3AN
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Posts: 787




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« Reply #1 on: December 27, 2002, 10:17:05 PM »

A QST "Hink and Kink" from long ago suggested using bond paper (not the usual cheap copy paper). It has some abraisive quality, but doesn't remove a lot of the contact metal as a file would. I used this to keep the unsealed relays in a FT-707 working. Each treatment would last about 6 months.

Take a small strip of the bond paper, place it between the contacts, and then use your fingers or some kind of tool to hold the contacts together. Then drag the strip of paper out from between the contacts. Repeat this 10 or so times.

Then plan on doing it again in 6 or so months ;-)
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KL7IPV
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Posts: 984




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« Reply #2 on: December 28, 2002, 12:51:32 AM »

After many years of cleaning telephone relay contacts, I think I can help you. First use a burnishing tool to clean the contacts and then use the bond paper to remove any residue. Hold the contacts together LIGHTLY. You only want to remove the residue and polish the contact surfaces, you do not want to remove any metal from the contacts. If the surfaces are really dirty, a contact cleaner can be used to loosen the dirt but not much is needed. The burnisher will do the rest. If you use the radio alot and the environment is dusty, you can plan on cleaning the contact regularly. If you can find a plastic cover for the relay and contacts, that would help reduce the need for cleaning so often. Good luck.
73
Frank
KL7IPV
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W5RB
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Posts: 565




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« Reply #3 on: December 28, 2002, 02:47:46 AM »

GC Electronics makes relay burnishing tools that you can buy for a buck or so .Check your local parts store , or order from Digi-Key or Mouser .NTE Electronics has an extensive line of replacement relays , probably  has one for your application .Find them at  the sources above , or on the web at www.nteinc.com  . For touch-up , try burnishing with a new dollar bill . If your relay needs frequent cleaning , it probably should be replaced .
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AC5UP
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Posts: 3834




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« Reply #4 on: December 28, 2002, 01:00:20 PM »

I have a hunch there's a new relay purchase (or chassis modification) in your future, so this advice is given in the spirit of postponing the inevitable...

Since you've already worked the contacts with a jeweler's file, chances are the surfaces are a little rough at the microscopic level and may have developed some new pitting. If you have access to some De-Oxit contact conditioner (expensive and hard to find, but it works!) wet the surfaces, let it soak for an hour or more, then work the contacts with the finest grit crocus cloth you can find at your local auto body / painters supply outfit. Cut the cloth into thin strips, use light pressure, flip the paper frequently (both cutting side and direction), and take your time until the surfaces look polished. Use bond paper as mentioned previously for the last few passes, and I prefer to work 'wet' when polishing surfaces. In other words, wet the paper then drag it through.

A few weeks ago I discovered that Lowe's carries CRC 2-26 "Lubricant spray with electrical properties" which is the poor-boy version of De-Oxit. It's intended to clean, lubricate, and penetrate contact surfaces to increase their electrical conductivity and reliability.

That sounds like what you're looking for...

For more info, visit:

http://www.crcindustries.com/productinfo.asp?productno=02004

and

http://www.crcindustries.com/waterdamage.asp


- AC5UP
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AC5E
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Posts: 3585




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« Reply #5 on: December 28, 2002, 05:55:52 PM »

HI: The GC relay burnishing tool does work, and I probably have a dozen around my various work benches. Rag based bond paper works about as well - a nice crisp dollar bill works even better. Or if you are a high roller break open a pack of your mint wrapped hundreds.

But once the plating has deteriorated buffing relay contacts is a losing proposition. The intervals between re-buffing keeps getting shorter and shorter. So I would start looking for a satisfactory replacement. I don't know what you need but your local GTE distributors catalog has quite a variety of available relays.

73  Pete Allen  AC5E
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