Turn the game off when unplugging boards and measuring resistance. Test resistors with the meter set to Ω . Put the leads on either end and see what you get. The number you get can be affected by other devices in parallel with the part being tested.
4543 decoder chips here: https://www.greatplainselectronics.com/products.asp?cat=11&pg=3
Put it in a socket. I like the SIP strips at the top of the page - they snap to length to fit any chip. : https://www.greatplainselectronics.com/products.asp?cat=161
While you're at it, get some 1/2 watt 100KΩ resistors and replace R26, R30, R32, R33, R34, R39, and R44 on all four player displays as well as R1, R3, R5, R7, R9, and R11 on the credit/match board. Might as well if they're out getting header pins soldered. https://www.greatplainselectronics.com/RCF_Half.asp