Hello.

Has anyone here replaced those two caps in the JBL 4311 crossover ? They are made of cardboard. I am assuming those should go and something newer should be there.

The caps say this:

T.I.
11937
3UF-0+10%
200VDC
mexico

and

T.I.
10391
8UF-0+10%
200VDC
mexico

I have recapped but never a crossover yet.

The pots still seem to have it. Maybe spray something in those and then replace these two caps and see if that does it for another 20 years or so.

Anybody know good replacement parts for those caps?

Regards

3.3 uf and 8.2 uf 250V Dayton polypropylene cap is what I would use in that case.

get those at:


Metalized Polypropylene Capacitors in the Electronic Parts Department at Parts Express | 1382

Thank you Dr. Techno. I've ordered those parts.

Are those polarized caps ?

On the original carboard caps the leads coming out of the 3uf cap are both orange and the leads coming out of the 8uf cap are both green. So, how do goes to a connector marked '3' on the alps pot and the other one goes to a punch down.

Does it matter which lead goes to to what ?

I am excited to refurb these crossovers as the brilliance and presence controls on the speakers do very little right now.

Regards.

MPP caps are not polarized. insert them either way.

Make sure you mechanically secure them with something other than solder....




-tINY

Thank you Tiny. I'll report back and let the thread know how it went.

Cheers.

So. I plunked those caps into those speakers. I used a hair dryer on the old caps and between the glue melting and the wax of the old capacitors melting that was quite a mess. I secured the new caps to the board with wire ties going through drilled holes and used heat shrink on the exposed wires and 3%AG solder (for fanciness).

The speakers sound better than before. The presence knob turns the tweeter right up into the pain zone, I still can't tell what the 'brilliance' knob is doing. However, it's not the first time that I have failed to recognize brilliance!

Anyways, without squinting, I can say is that the speakers have better treble and more of it, and they sound more stereo. They may also have more bass now. They sound a lot like newer JBLs that I have heard and they sound very modern for a loudspeaker from the 70's.

Thank you for helping me with your useful advice.

Good to hear that a pair of old war horses found a new life.



-tINY

glad that it worked for you like it did my 4312's