Examining Your Stylus
- Cotton swab(s)
- Isopropyl alcohol
- Blue Tack or other sticky, quick-release, removeable putty
- Microscope (laboratory grade with fine focus) with at least 80 - 100 power
- High-intensity lamp for above-stage illumination
The diamond tip of the stylus makes contact with the groove at two points. Over time, the tip wears at these two points and, in extreme wear, takes on a chisel shape.
Prior to that extreme, the original, rounded, contact points start to become flat. The trick in looking at the diamond is to judge when these flat points (flats) start to develop and at what point to replace the stylus.
An unused diamond stylus has an even polish. As it is used, the contact points on either side (where the diamond touches the groove walls) become even more highly polished. It is after this first high polish that wear begins.
Cleaning the Stylus
Before looking at the stylus, it must be cleaned. Moisten a cotton swab with isopropyl alcohol. (The swab must not be too wet or the alcohol can travel up the cantilever and cause damage to the cantilever suspension.)
Next, bring the swab's tip in contact with the stylus tip and gently twirl the swab. Be very careful not to flex the cantilever any more than needed to maintain contact between the swab and the diamond tip.
If dirt remains on the diamond, this process can be repeated.
Set the microscope up in a comfortable viewing position and shine the high-intensity lamp on the stage. Stick a bit of the Blue Tack on the stage.
Place the stylus assembly on the Blue Tack and adjust the assembly so that the diamond tip can be viewed through the microscope. The stylus must be placed so that the view is of one side of the diamond tip. (Both sides will need to be looked at.)
What I usually do is raise the objective so that it is well clear of the stylus. Next I remove the ocular (eyepiece) and look down the microscope tube. It is now possible to see the cantilever assembly and move the stylus assembly so that the putty holds everything in position with the diamond tip centered under the microscope's objective lens. Now I look around to find what I did with the ocular and put it back in place.
Examining the Diamond
Now comes the sensitive part. You want to focus on the diamond tip. You also do not want to smash the objective lens into it. The only advantage to smashing the lens into the stylus is that you will no longer need to examine it for wear -- the cantilever will have had it.
As you bring the diamond into focus you may well need to reorient the stylus assembly to:
1. Center the diamond in the field of view, and 2. Move the stylus so that the objective lens can come close enough to the diamond tip without hitting the rest of the assembly.
Shine the light directly onto the diamond.
Once everything is in focus, move the light about. As the light moves, it is possible to get an idea of the "roundness" of the side of the stylus and whether a flat is developing
Be sure to examine both sides of the diamond. (By seeing if one face is wearing faster than the other it is possible -- over time -- to get the anti-skating mechanism finely adjusted!)
I rarely look at the stylus head on. By the time wear shows in this view (flats on both sides of the tip) it is past time for replacing the stylus.
The same techniques can be used to examine the stylus of those cartridges with fixed styli. It's just a bit fussier when you have to put the whole cartridge under the microscope.
© John Fink 2004