I have just purchased and assembled two K8059 transmitters. One works fine but the second one has a problem. As soon as I connect the battery, the LED starts flashing. Pushing the Program button stops it from flashing but the other two buttons do nothing. I have checked for dry joints, short circuits and ensured that the buttons actually switch correctly. I have also swapped the IC and ensured all components are fitted correctly and in the correct place. Does anyone have any ideas?
For some reason, either the left or right button remains pushed.
Check with receiver which button remains pushed, this will help you to better locate the source of troubles.
Check diode direction, measure pushbutton continuity, check for touching solderjoints or solder bridges or PCB etching errors (unlikely). Make sure pull-up resistor value is correct.
I eventually tracked it down to an etching problem between one end of R5 and the negative rail. Having removed it all is now fine.