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WullieD20
11-25-2009, 04:17 AM
Hi guys,

I wondered if anyone had any useful tips on how to free (or relieve!) a 12" bass driver from its enclosure (a K2 S5800)?

I've released all the machine screws, but the driver seems to be stuck fast against the cabinet / gasket, even after using some reasonable force to pull it free.

Unfortunately, there's no way of exerting any leverage on the unit as there is a soft plastic surround that would be damaged.

I've done a number of jobs on speakers, including building my own and re-coning a pair of 120Ti's, but never come across anything so stubborn as these!!! :banghead:

Any tips or advice will be most gratefully received,

Cheers,

W

jcrobso
11-25-2009, 07:51 AM
Hi guys,

I wondered if anyone had any useful tips on how to free (or relieve!) a 12" bass driver from its enclosure (a K2 S5800)?

I've released all the machine screws, but the driver seems to be stuck fast against the cabinet / gasket, even after using some reasonable force to pull it free.

Unfortunately, there's no way of exerting any leverage on the unit as there is a soft plastic surround that would be damaged.

I've done a number of jobs on speakers, including building my own and re-coning a pair of 120Ti's, but never come across anything so stubborn as these!!! :banghead:

Any tips or advice will be most gratefully received,

Cheers,

W

Because of the gasket the driver is stuck to the board. If I was doing this I would get a couple of small putty knifes and lay them flat on them on the baffle and slowly work them under the speaker and lift just a little, slowly work your way around the speaker. After doing this you should be able to remove the speaker, best of luck to you.:)

WullieD20
11-25-2009, 10:57 AM
Because of the gasket the driver is stuck to the board. If I was doing this I would get a couple of small putty knifes and lay them flat on them on the baffle and slowly work them under the speaker and lift just a little, slowly work your way around the speaker. After doing this you should be able to remove the speaker, best of luck to you.:)

Thanks jcrobso,

Firstly, I'm trying to remove the drivers because there is a 'false' front plastic baffle that surrounds the driver and is apparently held in position with "double sided tape"!!!! Very poor construction method for a speaker of this calibre. Anyway, the tape loses it adhesive qualities over time and the plastic baffle begins to part company from the main cabinet. However, it is held in at the bottom by the horn, so it begins to lean outwards at the top, whilst remaining in position at the bottom.

I have been informed that the JBL repair technique is to remove the drivers, remove the offending panel, clean off all the double sided tape adhesive residue and replace the panel with impact adhesive.

Unfortunately, as I said previously, this plastic panel is countoured around the driver and is flush with the front of the cage flange, so it's impossible to get anything on to the cabinet baffle or behind the driver itself.

I've tried using a hook through the fastening hole in the driver and pulling, but this mother is tight! I suspect I shall just have to persevere with the hook idea and work my way round the driver pulling at every position possible.

Earl K
11-25-2009, 11:20 AM
Firstly, I'm trying to remove the drivers because there is a 'false' front plastic baffle that surrounds the driver and is apparently held in position with "double sided tape"!!!!

- Here's the tech sheet for the S5800. (http://manuals.harman.com/JBL/HOM/Technical%20Sheet/K2S5800%20ts.pdf) ( I'm not sure if you have it ).
- Does your understanding of this plastic facia agree with what's seen in the exploded view found on page 3 ?

<> cheers

WullieD20
11-25-2009, 12:18 PM
- Here's the tech sheet for the S5800. (http://manuals.harman.com/JBL/HOM/Technical%20Sheet/K2S5800%20ts.pdf) ( I'm not sure if you have it ).
- Does your understanding of this plastic facia agree with what's seen in the exploded view found on page 3 ?

<> cheers

Yes, absolutely! I have the tech sheet and I do know what I'm talking about. The item in question is No 25 in the tech sheet and is:
25 339358-002 BAF, UPPER, FINISHED.

If you manage to find a well lit photo of the S5800 on the web (better than my avatar!) you will see that it's the pale grey panel that retains the rubber sleeves that the grills locate into.

macaroonie
11-25-2009, 12:20 PM
Hope this helps everyones understanding

WullieD20
11-25-2009, 12:27 PM
Hope this helps everyones understanding

Hi Mac; Long time, no .... How's tricks?

I've already had one of these monsters repaired professionally under warranty for the same defect, but the second one has take two years to develop and the job in principle is really not difficult. Once the drivers are free the repair is a doddle, but both 12" drivers are stuck fast when all the fastenings have been removed.

I desperately don't want to damage any part of the enclosure or the fascia panels.

Cheers .

timc
11-25-2009, 01:04 PM
What about using a rubber hammer and gently give the Woofer basket some knocks?


-Tim

Eaulive
11-25-2009, 07:33 PM
Can't you remove the horn or the connector plate and push the woofer out from the inside?

BMWCCA
11-25-2009, 07:40 PM
Looks to be access to push on the back of the lower woofer through the rear port? Removing that should give you room to work on removing the upper one. :dont-know

WullieD20
11-27-2009, 03:02 AM
What about using a rubber hammer and gently give the Woofer basket some knocks?
-Tim


Can't you remove the horn or the connector plate and push the woofer out from the inside?


Looks to be access to push on the back of the lower woofer through the rear port? Removing that should give you room to work on removing the upper one. :dont-know

Hi guys,

SITREP:
I'd just like to say cheers for your ideas and participation. :cheers:
WRT the rubber hammer, unfortunately there's absolutely nowhere to hit the ***** thing!

The horn cannot be removed until at least one of the woofers has been removed, 'cause it's retained from inside the cabinet.

I can reach the back of the bottom woofer motor assembly through the ports (the crossover connection panel also cannot be removed at this juncture!), but although I've pushed and even knocked the woofer using a short shaft (not too hard' cause I'm fearful of causing damage!), the thing remains adamant that it's going to stay where it is!!!! :dont-know

I've 'hooked up' through the fastening holes of the cage and pulled like crazy, but nothing is giving at all at the moment. I've never come across anything so stubborn and it feels like I've left three or four of the retaining screws in position. Please be assured....I HAVEN'T!!! I'm convinced (and been assured by others) that it's just the periphery of the cage STUCK in position.

I feel like my only option is to put all the fastening back in, but leave them loose and play the speakers at full volume until such time as the drivers vibrate free.....:banghead::banghead::banghead:

Any further ideas would still be most welcome....

W

timc
11-27-2009, 03:31 AM
Maybe you misunderstood what i meant with the hammer.

I mean knocking on the front of the woofer. On the actual woofer frame.



-Tim

macaroonie
11-27-2009, 03:56 AM
The prob is caused by the resins in the cabinet paint and whatever gasket material is used becoming fused over time. This occurs partly because the coatings do not have sufficient time to cure totally before assembly but also because the gasket material is normally meant to remain flexible and hence will have resins that are very slow to set ( years ).
Have you tried to heat the rim of the driver with a hair drier. This should have the effect of softening the bond. I would suggest that you make a mask to protect the cone , cardboard would do and just appply some heat to the rim of the driver.

As an alternative liquid lighter fuel is pretty handy for softening 'adhesive' bonds

Of course quite how you get sufficient force to pull the driver is open to question. If you are doing this vertically be aware that the bottom of the frame will want to come out the way due to the weight of the mag assembly. This factor might be your friend but be careful because once it start to go it will all happen in a hurry.

A couple of pics would help no end.

hjames
11-27-2009, 06:14 AM
take a 2 x 4 and coat it with a towel.
Lay the cabinet on its face so its slightly tilted with the towel-2x4 under the top edge.
Lift the top edge of the cabinet 6 inches up off the 2x4, then let it fall.
If the speaker doesn't pop loose, try lifting that edge 12 inches.
repeat as necessary at 18inch, and then at 24 inches
- but if that doesn't do it, I wouldn't go much past 24 inches.




Hi guys,

SITREP:
I'd just like to say cheers for your ideas and participation. :cheers:
WRT the rubber hammer, unfortunately there's absolutely nowhere to hit the ***** thing!

:dont-know
:banghead::banghead::banghead:

Any further ideas would still be most welcome....

W

macaroonie
11-27-2009, 06:42 AM
:) I dont think the heat method is going to work now that I look at it. The front gasket will stop the frame from getting warm enough. However there is a nice little gap around the edge of the frame that will allow the afforementioned lighter fuel to be put in. Put speaker on its back to do this.
If you think about it there is nothing in the immediate vicinity that will be harmed by this, only the front of the baffle and the back of the trim plate. Actually the fuel will soften the double sided tape also. Do not be scared to give it a good soak. I used to use the same method for releasing arm boards from subchassis on turntables. Never had any damage as a consequence.
I would also suggest you have a think about a wee tool to get a firm hold through the screw holes , why not try a pop rivet , if you get one the right size you could squish it far enough to grab a hold but do not pop the mandrel. Then you have something to grab with mole grips or similar.
Your place of work might have something suitable given what they do there.

One more related thought , it puzzles me why manufacturers persist in setting up their drivers for mounting behind the baffle when they very seldom do so. When you consider the level of engineering development that does into some of these drivers would it be beyond the wit of the designers to provide a suitable gasket system for rearwards mounting and have a simple trim on top of the surround edge. Oh yes that would be the LE14 LE10 2108 etc

WullieD20
11-27-2009, 08:36 AM
Maybe you misunderstood what i meant with the hammer.
I mean knocking on the front of the woofer. On the actual woofer frame.
-Tim

Tim, no misunderstanding; I knew exactly what you meant, but now you can see the photo that Mac has posted (and the text he used to accurately describe the problem) you can see what I am faced with.

There is absolutely no part of the woofer chassis / cage that's exposed for knocking OR levering. Mac's got it dead right I think re the subsequent bonding that takes place after assembly and I suspect the lighter fuel trick may be the one to release this bond.

Once again, thanks to one and all for your thoughts and suggestions. I'll keep you posted....:)

macaroonie
11-27-2009, 08:42 AM
4.8 / 5 mm blind rivet does the trick , I tried it in a 2206 frame I have. once squished the rivet will not pull through the hole. The shortest that Scewfix have is 12 mm long so you will want to have the expansion happening just behind the frame. This is to avoid any excessive damage to the ( unseen ) hole in the baffle . The hole that accommodates the T nut is probably large enough that this would not be an issue however caution is advised.
If you dont have the rivet gear nip out to mine and I will fix you up , Drymen
PM sent


No disrespect Heather , I am used to doing some seemingly heavy handed things with high value audio gear but I would absolutely NOT be dropping these face down from any height. Also remember the front of the horn sticks out some.

WullieD20
11-27-2009, 09:03 AM
Mac,
PM reply sent, many thanks.

hjames
11-27-2009, 10:38 AM
None taken - pretty sure I tried that angled-drop on one of my 4341s to pop the 2234 loose.

I don't have a pair of those to hand and just figured a sudden jar from a shot drop might pop them loose.
But hands on certainly beats a working guess ...

Gotta scoott - have a great evening!




No disrespect Heather , I am used to doing some seemingly heavy handed things with high value audio gear but I would absolutely NOT be dropping these face down from any height. Also remember the front of the horn sticks out some.

timc
11-27-2009, 10:49 AM
Ah. ok.

Well...Can't complain that JBL don't make things rugged.


Maybe it should be renamed the S5800 indestructible.



-Tim

duaneage
12-05-2009, 08:48 PM
Use a guitar string and work it around the frame to cut through the gasket. it will lift right off. I used this technique several times, even on drivers RTV glued in place.
This is how they get windshields off BTW