Try a small piece of card stock between each of the 100s score reels EOS switches. The 100 pt relay coil is powered through a number of paths but this may be the easiest to test right off. You can see below that the coil is locked in via a switch on that 100 point relay when the relay pulls in. Then when one of the normally closed EOS switches opens, that path is broken. If you manually activate the relay, the coil should not lock on because you should have no path to ground through the EOS switches UNLESS it's one of the other paths in this section of the schematic. You could even consider doing this with the playfield disconnected.
Disclaimer: This schematic was from the 4 player version, so yours will not be exactly the same, but the methodology is likely similar.
