I would suspect with the acid damage on the old boards it may have corroded the old "Trifurcon" pins in the connectors
http://techniek.flipperwinkel.nl/ballyss/rep/index1.htm#connect"
I got my crimper from Amazon https://pinside.com/pinball/forum/topic/help-best-crimp-tool-for-repinning-connectors#post-3619102 https://www.amazon.com/HT-225D-Cycle-Ratchet-Crimping-interchangeable/dp/B007JLN93S
https://www.marcospecialties.com/pinball-parts/CT100S
https://www.marcospecialties.com/pinball-parts/CT156T