How do I troubleshoot a broken SAA3004 Remote control transmitter used in a remote control?
One thing to check is use digital camera or mobile phone camera and see IR output side when pressing the remote buttons, because IR signal is usually visible by digital camera but not by eyes. Then you know if output is there or not. Then check voltage on IR emitter while pressing button. Then you know if controller is sending signal to IR emitter or not. If yes but no IR output then IR led is dead. Work backwards. If old remote, possible that buttons are worn out also.