Does it have any markings you might be able to see? Even the other brown/pink/green/white etc connectors on the other board might have some identifier and they look quite similar if not in the same family - it might get you a manufacturer for example. 2.5mm (2.54mm = 0.1" pitch) is not helpful since it's very very common. Probably a Japanese manufacturer too if the whole thing is made in Japan - Japanese stuff is frequently kept "in house". Looked at the big ones like Tyco, Molex, Phoenix etc

Surely there's some forum covering restoring, collecting these sorts of things? I didn't even know what one is but there'll be something or someone somewhere.