The problem with this is that you need relay contacts that can take a lot of current, if switching a mains supply of 100W the current is tiny but switching this at low voltage will mean BIG contacts. If switching mains and extiguising the output with the SS shutter, the output will not continue as the PSUs run down discharging the caps. I know people who have variance with the S4i and S4p so it must be acceptable!
Note I stated 'can be switched' - the LED output could never pull a relay in as the LEDs series resistor is on the board so 2V @20mA - good luck finding a relay capable of switching AMPS with such a coil. No my intention was to use this 'signal' to switch a transistor to energise the relay. And no the Emission LED is NOT bi colour. the BiLED is for board status there is a separate emission LED output on all versions of th board.
The S4FB takes the shutter signal thats included in the JST for colour output and does not have anything to do with the PWM shutter output of the FB4. This remains functional as it should and my board has no influence on that and vice-versa
Rob