5V power on Allo Boss DAC

I have Volumio running on a stack of RPI4 + Allo Isolator v1.2 + Allo Boss DAC. I have powered the Isolator and DAC separately (Isolator powers RPI). I want to connect a 5V fan to cool the stack. But I am unable to get power on the J19 GPIO pins on the DAC. Going by the DAC tech manual pins 1 & 2 on J19 are marked 5V external power. And J20 feeds audio signal to a separate amp. So, where can I get 5V for a fan ?

If you are in Australia, Jaycar have a 5V fan.

Perhaps I was not clear. I have a 5V 0.2A fan and I need to power it to cool the stack. From which GPIO pins on the Boss DAC can I draw power ?