12-29-2016, 09:39 PM
Ron, from looking at the voltage readings my guess is that TR701 is bad.
This transistor is subject to a lot of abuse considering its base is directly connected to the tuning knob. Think of what happens to that transistor when you walk across the carpet and touch the knob on a cold winter day!
After you get the circuit working, it might make sense to add some protection diodes to the input to protect TR701 from being zapped by static charges.
This transistor is subject to a lot of abuse considering its base is directly connected to the tuning knob. Think of what happens to that transistor when you walk across the carpet and touch the knob on a cold winter day!
After you get the circuit working, it might make sense to add some protection diodes to the input to protect TR701 from being zapped by static charges.
