https://pinside.com/pinball/forum/topic/post-purchase-checklist
https://pinside.com/pinball/forum/topic/shop-job-master-checklist
(Also scanning pinside for "alien poker" topics AND system 6 topics will help get a sense of the range of possible issues -- such as replacing the 40-pin connector, and reflowing all header pins, no matter what, etc... connectors, connectors, connectors...)
Good luck with troubleshooting! You'll be at a new level once this thing boots up -- all in due time...
-mof

google: site:pinside.com "alien poker" "system 6"
also, learn what other titles are system 6, so you can search for those as well to find solutions that should work equally for all system 6's -- such as just getting it to boot the first time.

You got this man, step by step!
-mof

Please rephrase the question and options

You made the right choice.
From the player's POV angle (the angle that matters most), the brain sees that thicker top ridge on the Kings as normal.
-mof

Can't wait to see this thing light up and a video!
-mof

congrats !!!
video time !!!