I need help with fault finding a car alarm key fob transmitter and its receiver. If this is not the right group please point me in the right direction.
I have adapted an old no name car alarm Tx Rx to tell my computer to open my front gate and or the garage door.
For some time the operating range has been decreasing and my fix was to adjust the tuning capacitor in the Tx. Not the way to go I know.
At short range I can see the code being received on a CRO and the voltages around both ccts seem ok using a DMM.
Question 1. How do I determine which cct is at fault ?
Question 2. Is there a URL for cross-referencing transistors ?
I guess I'm asking if anyone has a crystal ball but any help would be appreciated.
Gordon