I'd like to troubleshoot and fix a broken remote control for a Guldmann ceiling lift that uses the SAA3004 remote control transmitter (documentation below in link). Can someone explain the tools required to do this, and the steps necessary to troubleshoot such a device? I just replaced the 9V battery being used in the remote, which powers the a circuit board (SAA3004). I've used a multi meter and I know the CPU is getting power. I've put the black part of the multi meter on the battery and the red onto Vss (page 10 below), and is showing 8.9V. I can provide additional information if necessary, and some images of the circuit board. And I have a remote control with a functioning circuit board, in case we need to compare with the broken circuit board.
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.