New diaphram

[David Ketley]

Hi Im just about to install anew diaphragm on my 813B but is it just a case of taking out the three screws at the rear of the unit or is it a lot more involved?
Whilst the units are out is it a worthwhile mod to replace the old connecting wires if so whats your recommendation?
It seems the input has to negotiate fuses and bulbs !!!!
Is it a worthwhile mod to bypass these?
Thanks
Dave

[doodlebug]

The diaphram will be exposed by pulling off the rear cap. You don't have to remove the driver from the woofer. It should have guide pins milled into the driver to realign the diaphram. Check inside the gap, however, to make sure there isn't crud in there. Vacuum out what can be removed then use sticky tape to pull out what you can. There have been better descriptions of how to do this so search some here.

On the wiring, etc, that's not where you should put your effort. I've got the 813As with the Altec drivers and love 'em. I took the time to update all the crossover caps with new ones of the same value. I believe there are pictures of some of this here at LH, too. This made quite a difference as some of the old caps were out of spec. As to the wiring, these are nice, well-made harnesses so I did not mess with that. I did clean all connections with DeOxit as I put the units back together. This includes the light bulb sockets, too. I would not recommend you bypass them as they are there for a reason: they'll absorb energy when things are running to close to maximum or if you pull a connection somewhere up the gain-chain and get a good pop! in the system. We've all done it......

Cheers,

David


These are awesomem speakers

[David Ketley]

Thanks for that David just got the system sounding really nice then this happens.
Dave

[David Ketley]

Just taken the screws out but there seems some resistance to taking off the top. Is this the correct way in? should I just lever off with a couple of screwdrivers. Sorry to be so cautious but these things are not cheap if I get it wrong!
Thanks
Dave

[grumpy]

could tap it a bit first... it just comes off. Note that there are wires from the
terminals to the diaphragm inside, so use -some- care taking it off :)

[subwoof]

Do mount your own tires on the rims? Re shingle your own roof? diaphrams don't just *drop* in - the procedure for doing this has been posted a number of times on this site.

Perhaps a careful reading of those threads will assist...

sub

[David Ketley]

Hi Subwoof having never even having the units out before I do appreciate your comments, are you saying I should get this done professionally?
Keeping in mind that just trying to transport the unit is asking for trouble I thought from the many posts describing the various diaphragms that it is possible to do without special tools? I have searched the site but have not been able to locate an exact description of how to do it! Keep in mind where I live in the UK is long way from any professionals.
As I say I do appreciate any help.
Dave

[cooky1257]

Hi,this helped me out.Just make sure you follow it to the letter!http://audioheritage.org/vbulletin/showpost.php?p=59479&postcount=14

[Mr. Widget]

Hi,this helped me out...I did a search for that post and I couldn't find it. I am glad you did.


Widget

[Robh3606]

#5. Trial fit the new diaphragm. Locating-pin holes are not always the same size as the locating pins. The diaphragm should fit snug on the pins but shouldn't need to be forced into place. If that's the case, the locating-pin holes need to be reamed out a bit....newer ceramic units have a relief machined into the top plate that the diaphragm drops into.


There are no pins in a 2425 so the alignment is basically inside the recess with the collored polarity pin lined up with either a JBL logo or a recess. The voice coil gap has a key to allow clearence for the return wire of the voice coil. When you look at the gap you will see a wider spot. Once you get the polarity mark, screws holes lined up and the coil in the gap Do Not Rotate the coil in the gap.

Rob:)

[David Ketley]

Thanks for the help I will keep you informed of progress once I have received the diaphragm.
Dave

[David Ketley]

My new diaphragm has arrived already from Sound Speaker Repair. ordered on 28th arrived with me in the UK today!

OK its only a cheap version but I want to check out the issues replacing this unit with a cheap one first then upgrade later if I feel it warrants it.

I'm still confused about the polarity issue very simply do you put the red on the terminal marked positive or very weird the black?!!!!!!
Thanks
Dave

[Robh3606]

When you pull open the back cap take out the digital camera and take some photo's. You can use the photo's as a reference before you disconnect the wiring.

Rob:)

[David Ketley]

Well that was not rocket science just the fear of the unknown. After a little gentle pressure the cap came off a treat took some picts with the camera, two screws to release the two feeds in, three to get the unit out was some slight damage, checked the gap for rubbish and back the new one went. Nothing! Still no H/F. Checked the bulb seemed Ok checked the fuse seemed Ok took the unit out checked the wireing all Ok. Back to the bulb and fuses shorted out the H/F fuse RESULT! H/F back.
So as Im running these speakers on unit on a domestic AV amp Onkyo 605 Im shorting out all the bulbs and fuses they are a real weak link in the chain and yes I reckon its sounds better too.
Back to listening to music Im fed up with messing about if it sounds Ok just play some music!
Thanks for all the advice
Dave

[louped garouv]

so, maybe the original diaphragms are still OK?