I dissected and drew up this oscillator circuit from a cassette machine the other night. It's purpose is for biasing the tape. I'm curious though as to how this oscillator functions since the base is not grounded. It measures a negative dcv at the base. It produces a clean hv ac sine wave after the 562 cap... but why, or how? What is the purpose of the bypass cap in the circuit? What would happen if the input voltage were increased?
Update The TO-92 says c3377 which seems comparable to a 2sc3377 npn transistor.
Also, I have been researching transistors without bias and came across this... "Ever wondered why VBE is always quoted as 6V for silicon transistors? The reason is that a zenner effect takes place at around 8V. Now, if you actually use a significantly higher voltage, but current limited via a resistor, then the zenner effect will allow enough base leakage current to pass to make the device conduct as if a bias had been applied. This conduction holds the emitter (now collector) at this zenner voltage." Is it possible this is how the circuit is functioning? After quadruple checking the pcb there are definitely no bias resistors on the base.
I have some parts coming and will breadboard it to verify the schem too.