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Re: May be silly question, but: Lost my qq(´) and qq(´) key

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On 2019.04.08 05:29, Martin wrote:
> since a few days, my qq(´) and qq(´)¹ don't work with a single
> press.  I have to press twice.

The problem most likely is oxidation of the electrical contacts of the 
key switch.  The silver or gold plating of the contact surfaces may be 
compromised by mechanical wear.

Back in the 1970's, keyswitches were rated in terms of tens of millions 
or hundreds of millions of keystrokes; keyswitches of today are rated in 
terms of tens of thousands or hundreds of thousands of keystrokes.  
Search and read the manufacturer specification sheets for keyswitches.

A factor which exacerbates the situation is the ongoing effort to reduce 
energy consumption; nowadays voltages across keyswitch contacts can be 
too low to break through oxidation and the currents flowing through 
contacts may be too low to burn off the oxidation.

Research years ago by Honeywell Corporation revealed that gold-plated 
contacts are not always a good approach.  Though gold does not oxidize, 
the presence of oil vapour in the atmosphere can result in formation of 
an insulating polymer on gold contact surfaces.  Silver contacts appear 
to be the proper approach; silver oxide is conductive.

Mechanic design of the contacts also is a factor; when the contacts are 
bars or rods which cross at an angle, the contact pressure is higher 
pressure than if the contacts are in the shape of buttons.  The pressure 
helps break through oxidation.

Some manufacturers offer "lifetime" keyboards; but the lifetime in view 
appears to be that of the keyboard and not of the user.  Keyboards today 
can have a useful lifetime measured in months.  Much depends upon the 
environment in which the keyboard is used, particularly the atmospheric 
humidity.

The proper approach to the problem of low voltage and low current would 
be to design keyboards in which the keyswitch contact voltage and 
current are an order-of-magnitude higher than the voltage and current of 
the logic circuitry.

RLH

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Thread

May be silly question, but: Lost my qq(´) and qq(´) key Martin <keine-eile@online.de> - 2019-04-08 12:40 +0200
  Re: May be silly question, but: Lost my qq(´) and qq(´) key Markus Schönhaber <debian-user@list-post.mks-mail.de> - 2019-04-08 12:50 +0200
    Re: May be silly question, but: Lost my qq(´) and qq(´) key Martin <keine-eile@online.de> - 2019-04-08 13:30 +0200
  Re: May be silly question, but: Lost my qq(´) and qq(´) key Eike Lantzsch <zp6cge@gmx.net> - 2019-04-08 14:10 +0200
    Re: May be silly question, but: Lost my qq(´) and qq(´) key Martin <keine-eile@online.de> - 2019-04-08 14:20 +0200
  Re: May be silly question, but: Lost my qq(´) and qq(´) key rlharris@oplink.net - 2019-04-08 20:30 +0200
    Re: May be silly question, but: Lost my qq(´) and qq(´) key Dan Ritter <dsr@randomstring.org> - 2019-04-08 21:30 +0200
      Re: May be silly question, but: Lost my qq(´) and qq(´) key rlharris@oplink.net - 2019-04-08 22:00 +0200
  Fixed: May be silly question, but: Lost my qq(´) and qq(´) key Martin <keine-eile@online.de> - 2019-04-11 10:30 +0200
    Re: Fixed: May be silly question, but: Lost my qq(´) and qq(´) key Reco <recoverym4n@enotuniq.net> - 2019-04-11 14:20 +0200

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