[pianotech] Center Pin Zapper

[Mark Purney]

 From the limited info I've been able to dig up, it seems that this 
device works by simply connecting each end of the center pin to the AC 
output voltage of a step-down transformer. Del Fandrich's zapper 
apparently used a transformer that converted 120VAC to 6.3VAC (not 
rectified DC, just AC).

For those of you who have built these zappers, does that sound like what 
you've done (less the switch and buzzer)?  I've heard that some people 
use doorbell transformers, but the output voltage of a doorbell 
transformer can be anything from 6VAC to 16VAC, depending on the type of 
transformer. I'd think the lower, 6V output would be safer and make it 
easier to control the application, thus protecting the birds eye part of 
the flange from being overheated.

I know this device doesn't work for all cases, but I have some clients 
that I'm sure would appreciate the cost savings if I could solve their 
center pin problems without having to repin every flange.