Reusing power supply from HP LaserJet RM1-5315

[DarinC]

I'd like to repurpose this power supply into another project. Could someone give me tips on what to connect to get it to power on. I assumed it would be simple like turning on an ATX (connecting green to ground) but I haven't figured it out yet.

[DarinC]

I guess its not as simple as I would have imagined

[R_J]

Based on the picture you provided (from amazon) there is no way to tell. Post clear hi res pictures of both sides of YOUR board and we may be able to trace the circuit.
There are two optocouplers on this board, one is likely for power supply feedback regulation, the other one could be the one that powers on the supply.

[redwire]

The PC board has text labels for the wires, such as "3.3V" and "REMO" on the small connector...
I don't think it ever really shuts off? Unless it goes into some low voltage mode like Canon printers.

[faraday28]

Yes you can power this up, but once you plug the Line Input it will running, there is no standby mode. Standby mode in printer usually only on the main board, the power supply is actually running 100% but it doesn't draw much because the main board goes to standby mode.

Attached picture for explanation what parts on your power supply.