display doesnt light up ballys s5500

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Hi everyone,i just got another project,its a ballys s5500 quarter blazing sevens 3 reel,i replaced the battery and did a ram clear and it worked reels turned i could hit the tiny button on door and get credits and pull handle,,but the coin compairator wasnt working,went to change that now i get no display on door,nothing and pushing tiny button stopped,the reels turn when i reboot here and there but not everytime,plus the red led on mpu next to reset glows red,,,what happened,one more thing this has 2 banks of dip switches could somebody please tell me what they are supposed to be set at,,,,like i said i replaced the battery and did a clear,took a few times but everything worked but coin comparitor ,now nothing works,,changed power supply and still the same,the transformer looked crappy so i ordered one,,,could that be the issue??so all in all what are dip settings and why no display,thanks alot ahead of time