Cat's Whisker

[trev757]

I have a crystal set where the crystal in the cat's whisker appears to be defective.  If I replace the Cat's Whisker with a Germanium diode the set works fine.

These things are not my area of expertise and wonder whether the crystal can be replaced in it's holder with a new piece.  You can get galena crystal for pennies on line, so it would be good if I could effect a repair.

Can anyone advise please?

[peter scott]

Go for it!

Peter

[trev757]

Thanks Peter.

Do you know how you change the crystal?  Do you just chip out the old stuff until you have a good clean surface on the holder and then use some glue to keep the new crystal in place? Also, how do you make the electrical connection between the crystal and the holder? 

[boater sam]

Thanks Peter.

Do you know how you change the crystal?  Do you just chip out the old stuff until you have a good clean surface on the holder and then use some glue to keep the new crystal in place? Also, how do you make the electrical connection between the crystal and the holder? 

They were held in with low melting point metal, wood's metal comes to mind, so that there is good conductivity. You should be able to fit a new "crystal" using the old metal.
Never done it though.

[peter scott]

Conductive epoxy might substitute for Woods metal. I think I've seen holders with a screwed bezel with the rim gripping the crystal against the back of the holder.

Peter

[reset]

I have a crystal set where the crystal in the cat's whisker appears to be defective.  If I replace the Cat's Whisker with a Germanium diode the set works fine.

These things are not my area of expertise and wonder whether the crystal can be replaced in it's holder with a new piece.  You can get galena crystal for pennies on line, so it would be good if I could effect a repair.

Can anyone advise please?

   



  mount crystal.pdf (Size: 705.12 KB / Downloads: 6)

[Kalee20]

Super info from Greg there

With melting point 158 deg F, you should be able to melt out the old one by putting it in boiling water. You'll recover almost all the Woods metal, too.

A quick Google search showed up suppliers, £33 for a kilogram of the stuff, if not - readily available.

[trev757]

Thanks for all the suggestions guys.  I've just immersed the crystal in boiling water and hey presto!  I have a piece of crystal, an empty holder and a nice little lump of low melting point "solder" which I can re-use!  I will now order a piece of crystal and have a go at re-assembly.  Does anyone know if you can just hack away at the new crystal until you get the size you want with a relatively flat surface to mount in the holder, or do you have to be more precise.  Thanks again, Trev.