Are those Cornwall IIs?
I acquired a pair of Cornwall IIs last year (circa 1986) and rebuilt the crossovers as a matter of maintenance. I found a solder joint that was pretty questionable, so I’m glad I did. I guess you could start troubleshooting and pull a lead from every driver except the squawker, and with a pink noise signal at a constant spl and an spl meter at s fixed close distance, see what you find. If you keep the variables as close to the same as possible and one squwaker is louder you can then troubleshoot further to see if it’s a diaphragm issue or a crossover issue.
There are a lot of smart guys on this board who will probably chime in with a better test but that’s one way.
Here are what my crossovers looked like after I rebuilt them