One of the odd projects that has come my way is a pair of 2-way Knight KN2360 speakers with unbranded, but clearly JBL-manufactured drivers. No JBL labels, but tweeters that look like LE20-1, PR-10 passive radiators (such as were used in JBL Lancer 77's), and 123-1 woofers. Everything works, except for one tweeter (used LE20-1 ordered). They must be at least 40, maybe 50 years old. The crossover looks like a resistor between the L-pad and the tweeter, never saw anything else like it. Crossovers may need help due to age, but I don't know how to tell. Except for the passive radiator instead of a port, I've been given to believe the speaker most similar to these in the official JBL line would have been Lancer L-88 (the 88's apparently used the same drivers). These have linen fabric grilles, very discolored now but must have been closer to white originally; they look almost like classic AR speakers until you get close enough to realize they aren't. (It must have been the fashion for a time, because I have seen some Bozaks with linen grilles also.)
Does anyone recognize these? Are they worth trying to repair, even just for the experience, or would I do as well to just part out the other working drivers? How does one test a capacitor or determine what value to use to achieve a certain known crossover point (in this case, 2000 Hz)? I'm still a newbie at repair, but I've done enough reading to know that I only know enough to be dangerous; the more I read, so far I still only gather more questions than answers. I suspect (or at least hope) that somewhere further down the road comes a tipping point where one begins to know at least a little about what he's doing and why. But since I'm not there yet, I seek the experience of others who are willing to share it. Going to replace the bad tweeter with a good one, but then what? Any suggestions?
