Replacing the Diaphragm on the K-76, K79 and Others

 

This will be a set of instructions for replacing the diaphragm in the following Klipsch tweeters.

K-76, K-63, K-74, K-75, K-76, K-79, K-83, K-84, K-85, K-88, K-90, K63, K74, K75, K76, K83, K84, K85, K88, K90

These all use the same diaphragms and all can use either our Poly or Titanium diaphragms.

NOTE:  Do not touch the titanium dome of the titanium diaphragms.  The dome is extremely fragile and easily dented.  Handle only by the plastic ring that surrounds the titanium dome.

Concerining the thin plastic on one side of the diaphragm assembly.  I get lots of questions about whether to remove that or not.  I always leave it on, but it is so thin that I doubt it makes any difference if it is on or off.

This is a K-74 tweeter with a bad original diaphragm.

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We can measure the resistance at the tweeter terminals.  A good one will read about 8 ohms and a bad one will read open or infinite.

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OK, Let's get inside this tweeter.  Remove the three nuts holding the tweeter together.

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 Now we can separate the horn from the magnet assembly.  The diaphragm is on top of the magnet assembly.  


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Remove the old diaphragm from the magnet assembly.  Notice that this old original phenolic diaphragm has a damping pad inside it.  You do not have to be concerned with that.  The new diaphragm does not need it.

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We need to clean out the magnet gap.  Sometimes there will be pieces of the old coil or the coil former inside the gap.  I use a sticky note pad folded with the sticky out on both sides.  That will be run around the gap to get out any debris that might be in there.  One exception to that is that sometimes the manufacturer of the tweeter may have put ferro-fluid inside the magnet gap.  Ferro-fluid is a solution of magnetic particles in oil.  If that is in there (you would immediately know since it is an oily looking nasty mess) just leave it alone and replace the diaphragm.  It would be impossible to get all of it out.  It is in there for increased heat transfer to cool the voice coil.

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This is a new Poly type diaphragm.  Installation of the Titanium is the same.  You will find that there is one place that the diaphragm mounting holes perfectly fit over the locating screws and pins.  If it doesn't go on easy in the position you first choose, rotate it around to another position.

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 After placing the diaphragm in position, put the horn back on and reinstall the 3 nuts.  Tighten them alternately to seat the horn into position.   


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 That is all there is to it.  Now the new diaphragm is installed and measures good. 

 

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