Please see our youtube video on improving the shielding in the Pianet N:
Pianet N's suffer greatly from noise and poor tone. As of this writing, the original capacitors on the Pianet N are over 40 years old. Most capacitors, especially electrolytics, have a lifespan of less than 10 years. You will probably notice that these old electrolytic capacitors are "leaking goo" around the edges, which is a sure sign the capacitor is dead. The original polyester caps, particularly the .1k caps, become microphonic with age, picking up slight vibrations (such as key noise) and amplifying it into a loud "thunking" sound whenever a key is depressed. If you tap on one of these .1k capacitors with a wooden dowel while the unit is on, you will hear a loud knocking noise.The Clavinet.com Pianet N upgrade kit (available here) replaces these old parts with premium film caps and low-noise electrolytic caps (such as Wima and Nichon). Also included are two of the large value resistors (20M and 5.1M) in the Pianet N that tend to drift over time. Please view the upgrade schematic to verify that you have the proper version of the Pianet N before you purchase the kit. Because you will be working with high voltage capacitors, Clavinet.Com assumes no liability FOR PERSONAL INJURY OR PERSONAL PROPERTY CLAIMS RESULTING FROM THE USE OF THIS PRODUCT.