Normally, the paper cone color is a light gray. They sometimes fade a bit if left in direct sunlight. Usually a light wiping with a moist cloth is all that is needed to clean dust off, the moisture will dry.
Thank you for you very detailed response Mech986,
I see that you tinted them black with ink, hopefully the ink dried very well without damaging the cones or adding unwanted weight. The compressed pulp is originally vacuum dried into shape and held by whatever proprietary material / liquid that is part of the pulp slurry. Normally don't recommend ever wetting a JBL paper cone because we don't know what it might do to the structural integrity of the cone. That said, if for some reason the cone collapses or creases on hard excursion or driving, the JBL 127A or H (used in the L40A) woofer is not particularly hard or expensive to find and replace. You can get recone kits also to use but almost cheaper to just replace the whole woofer with an OEM original.
The India ink I used was very fast drying, i don’t think it added much or deformed the cones. I used a good quality paint brush and basic just gave it a fast single coat following the round of the cone, the KenRick Sound showed in their video.
Its not clear from the pics you've posted, do the cones look uniformly black or are they a little blotchy? Same for the tweeter flanges, they look like there's some black blotching around the edges and mounting holes. Flash pics will highlight visual defects. However, normally, the nice 3D grill cover should be in place.
The cones dried uniform and the blotchinng on the 033 flange is just some finger marks from the oil finish before I wiped them down.
Agree. If you want to do anything aside from DeOxiting the tweeter control, replace the two capacitors - one is a non-polar electrolytic and the other is a cardboard wrapped mylar. The NPE is 24uF and the mylar is 6uF. For the NPE, you can use a quality NPE replacement or a large (and usually expensive) film (metallized polyester or polypropylene) replacement. For the mylar, a polypropylene cap is recommended. Since you're in Montreal, consider purchasing from Parts Connexion, I've used their Axon caps with very good results. Leave the resistors and inductors alone.
http://manuals.harman.com/JBL/HOM/Technical Sheet/L40 ts.pdf
1. YES! The fiberglass basket is part of this particular speaker's design. Its an acoustic impedance loading the woofer and is integral to the acoustic box design. Suggest you retrieve it or rebuild it from 6" wide 1" thick compressed fiberglass strip material (normally used to wrap pipes) and refasten to cabinet. Also, do not add polyester stuffing, the cabinet should be lined with the original fiberglass material.
3. Nothing other than normal foam surround replacement for the woofer. Only investigate the 033 tweeter if it sounds tizzy or spitty in presentation. It is normally a pretty decent and smooth tweeter.
4. no additional bracing is needed. JBL cabinets are quite stout and well built.
IMO, the best thing to do for the speakers is to clean the cabinet veneers thoroughly and try to remove the plant ring stains. Some use a light amount of oxalic acid to lighten the area and then when improved, a light sanding will take it out. Some like using Murphy's wood soap to clean, especially if any smoke residue is noted. Once cleaned, a good mineral spirits wiping will remove any residue. Then a good inspection of the veneer for scratches or gouges which, if needed, can be raised with the moist towel / hot clothes iron method. A light sanding should get you smooth, then stain or oil finish. Others may prefer to use a poly finish but beware this will seal the veneer. Some would just simply clean, sand and use an oil finish, tung oil finish, Howard Restor-A-Finish and then Feed-N-Wax.
That plant pot ring was a bitch to work on, I tried everything oxalic acid and lots of sanding, it will not go away and I am scared to sand too much and go through the veneer, so I’ll see what I’ll do next...
JBL veneers respond well to good care and IMO, nothing looks better than a well restored JBL Walnut cabinet.