Notes:

1. Equipment and supplies needed for etching boards.
   • FeCl (ferric chloride) etchant. Approx 1 gal for 48 people.
   • Plastic trays
   • Laboratory coats
   • Safety glasses
   • Disposable polyethylene or latex gloves.
   • Nylon string to attach to boards being etched.
   • Plastic tongs to rescue boards lost in etchant bath.
   Provision for 12 people to etch simultaneously is sufficient to insure timely completion of this phase of the project in a group consisting of 24 people.
   
   
2. Equipment needed for tuning finished keyboards
   • Oscilloscope with provision for determining frequency.
   • Small screw driver.
   Two oscilloscopes for a group of 24 people is recommended.
   
   
3. Common problems and troubleshooting. The keyboard does not produce any sound the most common problems are:
   • No IC installed.
   • IC not installed properly.
   • No battery.
   • Battery leads attached backwards.
   • Short circuit by solder overflow in area of integrated circuit.
   • Poor solder connection somewhere in the circuit.
   • Board over etched and copper connections not complete (hairline breaks are also a possibility).
   • Defective speaker (rare but it does happen).
   • Circuit not drawn properly. Repair using wire jumpers.
   • Defective integrated circuit.