PCB connector advice

[drbible]

I need to power up this board but dont know for sure which pins are for 5v, GND, 12v etc. Can anyone help me work out which is which? I'll need to do the same for the video lines too but think I can figure that out from the old ribbon connector.
It's a galaxian bootleg on an EDM28 board. I need to power it to compare to a frogger one I'm trying to repair on the same type of board (diff power connector tho).

 

[grobda]

should be able to work it out from the other board. if not you can usually trace 5v and gnd from any ICs and 12v from the sound amp.

unless for some reason one is AC and the other DC. dont know these bootlegs.

 

[Retroman839]

 

[Retroman839]

These 2 are ground

Looks like previous owner tied the next pin along to ground which looks to go to the negative of the blue cap.

So this would make it a third ground

So 4 pins left …. You might have a -5v pin

 

[NivagSwerdna]

Assuming it does not have AC rectification on the board... choose an arbitrary device the bottom left hand corner is probably ground (check the datasheet if in doubt) use that to verify the grounds. the top right hand corner will be the +5V. You can probably follow back from the audio amp to find the +12. More exotic voltages will probably only occur if you have dynamic RAM which may require -5V.... if you have 4116s check for continuity from pin 1 of the 4116 to the edge.

If you post a photo of the whole board we could look to see if it includes rectification of AC?

 

[drbible]

No -5v I can see on the separated old power supply, only +5 and +12 (and '0').
Good tip ref checking continuity thx guys.
That test suggests that these pins are in fact +5v and not GND @Retroman839 ?
No idea about the audio amp - here's a pic of the board minus daughter.
So I think I've got the pins mostly indented. My guess is the 12v is as per the pic but I still don't know what was on one of the pins that has solder on it.

 

[NivagSwerdna]

Could the two pin connector be audio out? Hard to see from here