mortal kombat 2 jamma video issue

[ste]

hi, i power on my machine and all i get is well nothing blank screen,

so i checked inside the cab looked at the jamma board no power led. turns out the board had a cut line so i pactched that up with wire now i get power to the board but now no activity led
i removed all roms and processors gave them a clean and activity led lights up but does nothing more, still getting black screen. ive spent the last three days trying to get this cab working, reaching on the net and it seems there are alot of mk2 boards with the issues mine has but no alot of answers, im using a standered jamma psu and my multimeter is reading the +5v but not getting a reading on -5v which i suppect the case here being trying a new psu

because no matter what i do with my psu like turning the small knob to get -5v i instantly lose my +5v so in a no win situartion until i get a new psu maybe a differnert brand to see if the problem goes away.