To see if this supply is 230V or 115V, you only have to look in the first part of the supply.
I expect it to be as the attached schematic diagram
On the left you enter the mains (115 or 230V) then it will pass the fuse and the filter (on your photo the small transformer with the double coil on white plastic) from there it will go to the rectifier (the rectangular black block that is placed in an angle). from there the PLUS and MINUS will go to the electrolytic capacitors. (those big black cylindrical things in the middle)
BEWARE!!! those Elco's can hold leathal charges!! measure before you touch anything!
If this supply is 115V there should be a connection (a jumper or a wire/bridge) between the centretap (where the two elco's are connected to eachother) and one of the AC-inputs (~) of the rectifier.
In the diagram this is the green line.
If there is no connection, you probably have a 230V board. You might find a pair of holes in the PCB with a white printed line that could connect the centretap and AC-input.
I ommited all extra components in this diagram as their only function is to protect or suppress (filter)
Normaly the fuse will be rated higher for 115V. Maybe this value is printed on the PCB. Say, it should be 1.6At for 230V and 3.16At for 115V use. If there is a 1.6At fuse placed, then you probably have the wrong board (these values where just an example!)
Succes and be carefull!
Kees