104H repair question

[bigyank]

So one of my recently reconed mids (NOS C8R104 was used) has stopped playing music. :( I will cut to the chase and open it up to my esteemed colleagues here on my next possible course of action. If you look at the attached pic, seems that at the junction point of the circled tinsel lead and voice coil lead meet, if I tap it, I get sound and a DCR of 5.1 ohms, every time. Try it on the other one and nothing.So can I remove the glue on the cone side? Do I have to go at it from the rear (not much room)? Use Acetone to remove the glue? What glue should I use? Yank

[JeffW]

Those are poly-something cones, right? I don't know that I'd go after them with any solvent, but that still leaves the glue blob. Where are the leads to the VC, along the rear of the cone?
Good luck!

[Earl K]

So one of my recently reconed mids (NOS C8R104 was used) has stopped playing music. :( I will cut to the chase and open it up to my esteemed colleagues here on my next possible course of action. If you look at the attached pic, seems that at the junction point of the circled tinsel lead and voice coil lead meet, if I tap it, I get sound and a DCR of 5.1 ohms, every time. Try it on the other one and nothing.So can I remove the glue on the cone side? Do I have to go at it from the rear (not much room)? Use Acetone to remove the glue? What glue should I use? Yank

I would contact GordonW ( or Edgewound ), then describe the symptoms you've found & ask if it might be repaired ( you apparently believe the solder-joint is bad at the connection between one of voice-coil lead-ins & the litz-wire leading out to the terminals ) .

The cones are mineral filled, PolyPropylene ( AFAIK ) . I'd be wary of using any solvents ( or heat from a soldering tip ) around plastic like that ( best leave dangerous work like that to the experts ) .

:)

[bigyank]

I was going to try picking the lead where it is glued on the back of the cone with a dental pick. The amount of pressure needed is so slight I can tap out Morse code out to my DMM. I will let you can all know how I fare. Heard through an official reconer that the C8R104, amongst others will be available but with a slight price "adjustment". 222.00

[Earl K]

I wouldn't go picking away at the glue on the cone . That's a surefire way to break-away a piece of wire ( while it's encased in the glue ).

I would experiment with dissolving the glue ( on a glue-blob of your making, that's located on a sacrificial plastic surface ) .
- Polypropylene is widely used in the making of containers ( compare an example to your 104H cone for the purposes of identity ) .
- Research the "recycling number codes" to help identify your plastics "test subjects". Here ;

http://followgreenliving.com/wp-content/uploads/2014/05/codeee.gif

Use Acetone ( or MEK in a well ventilated room ) to test dissolving the glue ( while observing the effect on the plastic base ) .

You can buy JBL's preferred glue from quite a few online retailers . Google ; Moyen RS-3087

Here's one ( click the pick ) ;http://www.saveltd.co.uk/ekmps/shops/soundvision/images/speaker-diaphragm-glue-cement-jbl-pro-adhesive-any-brand-driver-repair-recone-4125-p.jpg (http://www.soundspeakerrepair.com/speaker-parts-p/RS-3087-Adhesive/Parts)

:)

[JeffW]

Heard through an official reconer that the C8R104, amongst others will be available but with a slight price "adjustment". 222.00

Did you ever try to contact the official reconer with the $95 price listed?

[grumpy]

There's one on ebay ... in Europe. Price, even with shipping, isn't too terrible.

[bigyank]

Did you ever try to contact the official reconer with the $95 price listed?

Yes I did Jeff. He is the one who recommended the picking of the glue method and not acetone as he believes it might react with the cone.

[bigyank]

There's one on ebay ... in Europe. Price, even with shipping, isn't too terrible.

Can't find it. We talking kit or driver grumpy?

[bigyank]

There's one on ebay ... in Europe. Price, even with shipping, isn't too terrible.

I found it. Only issue there is it has the wrong dust cap which leads be to believe it is an aftermaket recone. I can get this same configuration from OC:

http://www.speakerrepair.com/page/product/OCSRP386.html

"we can Recone your JBL 104H speakers for you. JBL no longer offers parts, but we have aftermarket parts that are built to the same specs. The only difference is some of the original 104H speakers had an aluminum dome. The new recone will have a paper dome. The recone cost is $85 per speaker plus shipping. "

Hence my reasoning for trying to fix it myself. I heard through Edgewound via PM that JBL is supposedly gearing up for a run in August 2014 timeframe. This is to include both the 104H's and LE14H-1's.

[grumpy]

Glad you could see more closely!

[bigyank]

I am so close to drilling out the connector plate's rivent. I have non-magnetic tools (stainless), and I just can't get in there!

A reconer source I have says to try:

Try reflowing the solder one eyelet at a time with your DMM connected. Way out of my league. I might just send the damn thing to OC for an aftermarket recone and using woofer tester (WT2) see how close to original it actually is. Damn! :shocking:

[JeffW]

Yes I did Jeff. He is the one who recommended the picking of the glue method and not acetone as he believes it might react with the cone.

I meant send the thing to OCS with $95 and get a working driver with a JBL kit in return.

[Don C]

104H-2s seem to be much more common on eBay. I don't think it would be considered a downgrade, as long as you swap them in pairs.

[bigyank]

From what I have read on this forum, that would require a major crossover redesign and possibly an mid enclosure change as well. If I can't get them going, then I might just part them out and keep the LE14H-1's which were reconed by edgewound using a custom aftermarket kit and aquaplas. These would be an awesome subwoofer (think Harman Kardon Citation 7.4). 2 of those mated to my SVA-1800's would rock the house literally.:D

[bigyank]

So thanks to a forum member I was ablessed to get the speakers back in action. I now even have a spare. This forum rocks. :D

[grumpy]

From what I have read on this forum, that would require a major crossover redesign and possibly an mid enclosure change as well.

I'll find out how big a deal this really is, soon (104H vs 104H-2). That hole in the 240Ti cab ain't gonna fill itself... :)

So, comparing the plots on the ol' le5 matrix thread, my initial thoughts are to increase the 240Ti MF section attenuation some 3-4dB,
shift up the LPF rolloff to a higher freq (no longer using or compensating for a significant rising response), and -maybe- tuck
the level down a bit at 1.8KHz (shallow notch). Will have a listen and a measure first.

[grumpy]

LOL, so I sent a message to Harman asking a question about a 240Ti part (screw for 044Ti, P/N 61145) and got this:



Thank you for contacting us. This is an automated response to confirm that your inquiry has been received and a case number has been assigned. We are currently dealing with an unexpectedly high volume of customer contacts, and are working very hard to get caught up. Please be patient. We will respond as soon as possible, and will do all we can to assist you. Please do not respond to this email, as it will not be received or answered. The Harman Team


So far so good. The very next email I get:




This notification is to confirm that your case was closed. You will not receive any further communication regarding this case but we would be happy to assist with any other questions you may have. Please contact us again if your case was not completely resolved or if you have any other questions.

Please take a few moments to complete our survey regarding your experience.

http://harmaninternational.force.com/survey/TakeSurvey?id...blah blah blah

Fail. Not entirely unexpected, but Fail. The email equivalent of being hung up on.
Now I know why they send people here. :banghead:

[grumpy]

So... 044Ti takes a 1 1/2" 8-32 screw.

and in a 240Ti, without being able to A/B the 104H and 104H-2,
I'm in no rush to modify the 104H-2 swap.

and yes, black oxide hardware is being ordered, now that I know the size.

[bigyank]

Looking good! Wonder myself how the 104H-2 will sound as well since they are more easily procured.

[grumpy]

I'd like to compare... listening and measuring, but have no 104H to try.

I did look at the published response curves though, and there are differences in both sensitivity and response. I cranked out a "fix" in Spice, given the FR and imp curves, but haven't tried it yet.

So, being itchy to hear something, I tried a straight swap anyway (no xover mods), left both mid and tweeter switches at 0dB (vs -2dB), and it doesn't sound "wrong"... maybe a bit bass heavy in the 60-80Hz range, but that could be where I have them or by design.

I did try the 2dB mid switch position, which seemed like a logical first cut given the sensitivity difference, but it sounded like a scooped EQ, so back to 0dB until I can be bothered to get out the test gear and see what's going on (compensating for the bass by boosting the mid(?). May have 044Ti's with gooey foam too, but one issue at a time :)