JBL 035Ti repair

[SaturationPt]

There's a seller on ebay who sells damper pads, not original but it looks like he did a good job when I compare his to new original ones I have.

Diaphragm kits DR8035Tia are NLA, there are some knock-offs available, not sure they're even titanium but it's what people are buying (it is the diaphragm and coil only, not the whole kit with the plastic flange and damper pads). If you use these I'd suggest replacing in pairs as I wouldn't expect them to be very close to the original and wouldn't match / image well with the original on the other channel.

Other than that you just have to watch for NOS and used as they come up occasionally.

 

[man00]

I recall some stuff that was used on hacking one of Intel CPU's..cut a pin or two run a trace to another pin and the would change the clock speed.
Seems during that time Intel was using the same CPU for different speeds. The "stuff" was a copper type liquid that would dry and conduct electrical current.
I bought a tiny bottle of it but I can not remember the name. I have the bottle I will try to find it, this may be a easier option for repairing these tweeters??

 

[sittingduck]

That sounds interesting - please do let us know what that stuff is called

 

[man00]

found it..Permatex Complete Rear Window Defogger Repair Kit
I don't know how well or even if it would work for this, but worked fine on the CPU as I recall

 

[moondogtn]

Interested to know if that Permatex works in situations such as these. I can see how it could possibly work. Some KLH tweeters have the same issue. I have read that it was caused by the glue or perhaps flux residue. I have had success with them performing almost identical repair. I do know is it’s not fun soldering tiny wire.

 

[man00]

I ordered some of those 69.00 tweeter knockoffs (035Ti, 035TIA) they sound fine to me. I can't hear any difference from the originals far as I remember. These were for the L100T. Next maybe recap or mod the crossovers..maybe not

 

[Maxmano356]

I picked up a quad of 4408's yesterday - No chance to demo & they are rough but cheap. One 035-Ti tweeter is out so I figured I would pull it apart to see what I could screw up. I did not see a break in the leads but even up close to the coil it was reading closed. So I pulled the leads free of the terminals and unwound a revolution of wire for each lead - still nothing. Then I put my test leads right on the coil itself and still had no reading. I'm just starting out trying to learn a bit about electronics so I have no idea why I'm getting these results. Can anybody offer an explanation?

Also - can anyone who has bought aftermarket diaphragms tell me id they have adhesive on them like the original?

Thanks!

 

[man00]

doesn't the copper wire have a insulation on it

 

[mech986]

doesn't the copper wire have a insulation on it

Yes, the voice coil wire is insulated, otherwise the windings would short out with each other. Therefore, just laying a DMM probe on top of the wire is not going to touch anything that is electrically conductive or get a reading. You have to test from a good and exposed metal piece like the terminals that the voice coil wire are soldered to. If there is no reading (infinite resistance), then more investigation through the wiring must be done. Remember, the voice coil wire is terribly small so any break may be hard to see.

 

[Maxmano356]

Ahhhh - that makes perfect sense. Now I wish I hadn't pulled the diaphragm off of the base.

Thanks for the knowledge!

 

[Mitkraft]

AK to the rescue again! I snagged a pair of JBL 4408 in goodwill several years ago with rotted foams. I'm not sure if I tested them at all but they've been in the garage waiting for me to get around to them. After finally completing my first refoam on another pair of speakers I decided to pull these out to make sure they were working well enough to order the foams. Was disappointed to find one tweeter bad. Did some googling, checked eBay and saw what was there and finally googled "jbl 035ti repair". Sure enough AK is the first result with this thread on top. Upon reexamination I found that I had a green spot just like the one below in Copa1934's picture but not quite as big. I ended up using a strand of Cat6e wire. Soldered it to the original hole on the spade connector but my original wire broke further back while trying to make a solder point for it. I ended up re-routing what was left off the side of the metal plate, cut a trough off the side of the original canal running from the spade and ran the replacement wire through it and into the indented area so it wouldn't cause a bulge since it was thicker than the original. After some fidgety work with my terrible solder skills I was finally able to make a solid connection! My Tweeter is alive! Now I'll order the foams for the driver. Thanks everyone who contributed!

As promised a couple images. Really should have taken more, but I was anticipating doing both tweeters and taking more detailed images, only to find out a spade connector was NOT connected. With the magnet assembly removed you can see the "lead" wires from the VC to the Terminals. In the first image there is a white powdery looking residue. That was wire, or I'll assume it was. I removed that from the channel where the remainder of the wire was. Because of the size and depth of the channel I decided to run a new "lead" using tinsel I had from another driver. I tinned both ends of the tinsel so it wouldn't fray AND for easier attachment of the remaining wire lead from the VC, which wasn't much to work with. Because the tinsel was "wicked" it fit more snuggly in the channel. I then laid the remaining lead ON the wicked end of the tinsel, applied the soldering iron to "bond" the two together. I then inserted the other end of the lead into the hole at the base of the terminal. Tested the driver and got a good reading. Installed the driver and we had music!

I have no clue why the wire had become powdery. Really weird. Looked like oxidation, but that doesn't make sense if it's copper. Anyone have some thoughts on this? Oh, there is adhesive used to hold the original leads in the channel. Had to remove that before installing the tinsel.

 

[Mitkraft]

Found pics on my phone from when I was trying to verify the damage. The small greenish spot in the trough coming from the spade connector is where the break was.

 

[Copa1934]

Wow, so happy to see this thread still helping people.Very cool.

 

[Fusternc]

Have been on the fence about replacing one of my 4408 tweeters at $70 and the surrounds on both woofers or just selling the set. So glad to have found this thread as it gives me hope!!! Thanks guys!

 

[Vintageaudio123]

Hi, I just finished repairing the two 035TI tweeters in my newly arrived L20T's (consumer version of the 4406) and then came across this thread. Had the exact same wire corrosion problem and both wires in both tweeters where open at one or two places, happy in a sense to find out its not something limited to my speakers because previous owner neglected them in some way. Had the tiny bits of blue green corrosion, probably CuSO4 (Copper Sulphate) so guessing something in there becomes really acidic over time. Also need to replace the damper foam in both as it has degraded, but so far they sound great, and the imaging of those TI tweeters is amazing. BTW earlier saw a seller on ebay offering those foam damper bits, and I believe he may be a member here and posted to this thread on page 1. Might be wrong, though.

My own repair thread is here with some pictures before/after of the wire repair:
https://audiokarma.org/forums/index.php?threads/jbl-l20t-crossover-schematic-cap-replacement.974152/

 

[33 1/4]

Hi, I just finished repairing the two 035TI tweeters in my newly arrived L20T's (consumer version of the 4406) and then came across this thread. Had the exact same wire corrosion problem and both wires in both tweeters where open at one or two places, happy in a sense to find out its not something limited to my speakers because previous owner neglected them in some way. Had the tiny bits of blue green corrosion, probably CuSO4 (Copper Sulphate) so guessing something in there becomes really acidic over time. Also need to replace the damper foam in both as it has degraded, but so far they sound great, and the imaging of those TI tweeters is amazing. BTW earlier saw a seller on ebay offering those foam damper bits, and I believe he may be a member here and posted to this thread on page 1. Might be wrong, though.

My own repair thread is here with some pictures before/after of the wire repair:
https://audiokarma.org/forums/index.php?threads/jbl-l20t-crossover-schematic-cap-replacement.974152/

I just picked up a pair of L20T with two dead Tweeters. How do you get the dome off to get to the 4 screws to get to the wire that I need to fix? Any help is much appreciated.

 

[milo63]

I just picked up a pair of L20T with two dead Tweeters. How do you get the dome off to get to the 4 screws to get to the wire that I need to fix? Any help is much appreciated.

Use a pick to remove the rubber O-ring around the screen.

Good luck!

 

[ossodiseppia]

I am so very happy I found this thread. I bought a pair of L80 3ts yesterday. One tweeter was reportedly blown. While searching for a set of replacement coils, I ran across this thread. I am really surprised this ever worked. The lead was wrapped around the terminal and looks to have only been soldered to the thin side of the terminal. A dab of solder and it's all fixed.

Thank you to al who suggested a broken lead!