Refurbishing JBL4312 speakers

[TerrapinBill]

Okay I have a bought speaker parts for my speakers I have the 035tia tweeters, 2213H woofers, and LE5-12 middies. Can I just replace the capacitors as it iset up for spec or do
I have to buy the OG parts meaning original tweeters, kids, and woofer?

[booja]

I'm new to this myself and I'm rebuilding some 4312As, but my focus is mostly cosmetic. I thought I read that the original caps are probably still ok on these crossovers. Do you think yours are faulty, or are you just wanting to replace them while you're at it? I know electrolytic caps have a limited lifespan, but none of the caps on my crossovers are that type.

For me the main problem was the L-pads. Turning them made some bad sounds, and when I opened them I could see the plastic parts of the wipers had melted, and the coils were deformed. So these are all I am replacing (for now). I bought NOS L-pads from eBay that are the same brand and model (Violet) but the shafts were too short. This meant I had to modify the way the crossovers are mounted and 3D print shaft extensions for the knobs. I have yet to put them all back together because I haven't applied new veneer yet.

[TerrapinBill]

I'm new to this myself and I'm rebuilding some 4312As, but my focus is mostly cosmetic. I thought I read that the original caps are probably still ok on these crossovers. Do you think yours are faulty, or are you just wanting to replace them while you're at it? I know electrolytic caps have a limited lifespan, but none of the caps on my crossovers are that type.

For me the main problem was the L-pads. Turning them made some bad sounds, and when I opened them I could see the plastic parts of the wipers had melted, and the coils were deformed. So these are all I am replacing (for now). I bought NOS L-pads from eBay that are the same brand and model (Violet) but the shafts were too short. This meant I had to modify the way the crossovers are mounted and 3D print shaft extensions for the knobs. I have yet to put them all back together because I haven't applied new veneer yet.

yeah these are old caps they will lose their performance over time. And now a days they have things that are half the size with better sounds. That crazy hour L-pads did that. I wonder what would happen to make them melt.

[booja]

yeah these are old caps they will lose their performance over time.

It depends. Aluminum electrolytics definitely age, leak, fail. But film type caps have a much longer lifespan and often are still ok unless overworked. I've found several crossover threads here and on AudioKarma where folks suggested leaving the originals in place. And of course some people like to replace them, but often it's with the goal of finding something 'better' than original.

In my case I lifted a leg on each existing capacitor and measured its value to see if it was still within spec.