You can get these crystal earpieces but they are often unreliable or stop working or have low output

they all seem to be made the same they range in price from about £2.50 up to £6

The main cause of failure is the connection to the aluminium diaphram inside which in the original is a piece of iffy copper glued onto the surface of the aluminium, highly suspect ...then that is fed underneath to the rear connection

My fix is to add another connection wire alongside this

see the following steps

I have repaired all 6 of my ones which were in varius stages of not working

one would work fine then just stop, others were low and distorted, one did not function at all

Step 1: Crystal Earpiece Repair 1

The first thing is to unscrew the clear ear plug and put that to one side

Next about 3 mm down from the front side edge you will see a contruction line where the top piece mounts onto the rear assembly... Put a mark across this to aid when refitting allignment

Taking a sharp knife score VERY CAREFULLY around the whole of the outside of the body

WATCH OUT FOR YOUR FINGERS go slowly BE VERY VERY CAREFULL

At one point press a little harder to get started enough to get a small sharpened 3mm flat screwdriver in

gently force the plastic apart using the flat blade....once started using the screwdriver blade slightly length ways seems to helps minimise any spliting

if it does start to split go around again with the knife..... the plastic is not very thick and should come apart fairly easily

once apart you should have the top part and the ally diaphram attatched to the rear assmbly as in the photo

notice the old connection tab and where to drill for the new wire ...see next step

Step 2: Crystal Earpiece Repair 2

Next turn the rear assembly over

remove the 1 screw holding the rear wire cover and remove the cover and place to one side

Next drill a small hole in the rear in the place shown in the pic BE CAREFULL not to pierce the diaphram go slowly

The rear cover will hide this later

Step 3: Crystal Earpiece Repair 3

Next You drill a small hole in the side as shown or you can try to prize up the ally diaphram a little to get the wire under

drill the hole to the Left of where the original tab connection is glued when viewed from the top diaphram

and with main audio lead at bottom

see position in photo above

I did the hole method as you could split the allminium if its stuck down too well

see picture

Step 4: Crystal Earpiece Repair 4

Feed that from the rear hole and out through the side hole

IT may help to pre bend the wire slightly to get it to curve out through the hole

see photos

Step 5: Crystal Earpiece Repair 5

Solder one end of the wire to the rear terminal as shown in the picture

Leaving the longest piece coming out from the side

you can refit the rear cover now with the screw

Step 6: Crystal Earpiece Repair 6

You now take the long wire bend it back on itself and you can poke the end just back in the hole again

and leave a loop that can be placed around the edge

(NOTE there was one instance of the poked back wire made contact with the lower diaphram connection.. if you do poke it back then only just in the hole OR maybe instead just lay the wire back on itself along the edge)

this helps make the new connection

see the photo