# Door switch contains small qty Ruthenium



## Chuck_Revised (Feb 25, 2008)

The door switch (on the imagesetter I tore down) utilizes a sensor with a reed switch that contains a small qty. of ruthenium.

It is a Hamlin part #59135 from 1997. According to the Hamlin website:

"The basic reed switch consists of two ferromagnetic nickel-iron wires and a glass capsule. The two wires are formed into "reeds" by flattening one end. The reed ends are carefully aligned with a small overlap and then permanently sealed inside the glass capsule. The overlap or contact area of the reeds is coated with special metals such as ruthenium. The nickel-iron leads are tin plated so that they can be soldered."

The door switch in this instance prevents the laser or power from operation if the door is open.


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## goldsilverpro (Feb 26, 2008)

When I was into plating, we sold Au/Pd alloy plating baths to reed switch manufacturers. They produced a white deposit on the reeds. Something else to look for.


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## macfixer01 (Feb 27, 2008)

goldsilverpro said:


> When I was into plating, we sold Au/Pd alloy plating baths to reed switch manufacturers. They produced a white deposit on the reeds. Something else to look for.





That's interesting. I've occasionally broken open small relays on circuit boards before which amounted to just a glass tubed reed switch inside a coil of copper wire, which was then potted inside a plastic case. I normally only saved the reeds if they appeared to be gold plated.

macfixer01


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