Replace PSU for 36V Bosch Industrial Screwdriver, wiring and plug info included

[Reprobyte]

I have a Bosch C-exact screwdriver which runs at 36V 1A - 36W, the PSU replacement is very very expensive, and therefore as it seems like I could buy a DC power supply for a 70th of the price, I had a look how its wired up and hope you can help clarify.

The plug used is a "BD509 S.693" and the wire used is "ÖLFLEX® FD 891 - Power and control cable for versatile use in power chains"

The wire has 2 black and earth, the two black are labelled "1" and "2"

The plug has 4 screw connectors, 1,2,3 and ground,

Which is positive and negative from the 1 and 2?

I assume my plan to wire to a 36V DC supply should work fine as long as I get the polarity correct, the Bosch PSU is only delivering the power, but for an extreme price.

Images attached, and thanks for any advice!