Can you please help me identity these symbols from a vintage (1960) diagram? The capacitors units are noted with "KP", sometimes just "K". What is the rectangle crossed with an arrow? It looks like a potentiometer without the tap connected.
1.what does kp means? pico farad?
2. what is this symbol? 5/6?
3. 47K farad?
4. 22k resistor or diode or bias pot?