Just shorting the LED should be enough.The most expedient way to get it to work is to short out the additional LEDs. You might also need to replace the resistors with something smaller than 3k.
The forward voltage of the LED inside the PC817 is 1.4V. The series resistors show in the photo look like 1K (102). With the LED shorted that would give 1.7mA for the opto input, which should be good.
Statistics: Posted by rpdom — Thu Dec 11, 2025 11:43 am