I was a bit too busy to mention it, but on my PreenFM 3 the top LED is not working, never did.
The LEDs on the mainboard do blink fine.
It's not important for me, maybe the blinking would bother me.
But I want to know, if this LED on the topside has a dedicated connection to the mainboard via the stackable connectors.
I have synced the PreenFM 3 to external device and with the internal clock, the LED doesn't work.