Ever see a driver split or the 2 pieces seperate?

[SUPERBEE]

I have a 175 driver that the back seems to be seperating from the front?

[Oldmics]

:useless:



Need to see what your talkin about.

Can you post a picture Super ????

Oldmics

[SUPERBEE]

Here tis...





:useless:



Need to see what your talkin about.

Can you post a picture Super ????

Oldmics

[edgewound]

Either it's been dropped which help the magnet discharge and separate the top-plate from the body...

Or....someone installed screws that were too long for the loading cap and pressed the plate apart.

I'm guessing the first though.

[SUPERBEE]

Either it's been dropped which help the magnet discharge and separate the top-plate from the body...

Or....someone installed screws that were too long for the loading cap and pressed the plate apart.

I'm guessing the first though.

It still has the redwax seals in place. I pulled it out of a cabinet it had been in for 51 years and I have not droped it. This seems to have happened in the last few days. It was not like this when I first removed it

Any way to fix this? Is it still usable?

[edgewound]

It still has the redwax seals in place. I pulled it out of a cabinet it had been in for 51 years and I have not droped it. This seems to have happened in the last few days. It was not like this when I first removed it

Any way to fix this? Is it still usable?

I didn't say you dropped it...but I doubt it left the factory like that.

You could try to tap it back together...the gap is certainly WAY out of kilter here....and it takes LOTS of force to get that kind of separation, unless the magnet is feeble.

I'm afraid any attempt to get it back together and working properly without disturbing the wax seals will take lots of prayer and luck. Most likely the gap is too narrow for a modern diaphragm should it become damaged.

Good luck with this one....hope you can save it.

[SUPERBEE]

Thanks EW

This is just making me sick. I actually bought this in Upland a few weeks ago.




I didn't say you dropped it...but I doubt it left the factory like that.

You could try to tap it back together...the gap is certainly WAY out of kilter here....and it takes LOTS of force to get that kind of separation, unless the magnet is feeble.

I'm afraid any attempt to get it back together and working properly without disturbing the wax seals will take lots of prayer and luck. Most likely the gap is too narrow for a modern diaphragm should it become damaged.

Good luck with this one....hope you can save it.

[robertbartsch]

Yeh, I feel your pain.

Anyway I bought an old Adcom amp a few months ago and now it is dumping DC into the speaker loads. I also have an old BMW that just blew a motor this week.

In short, OLD stuff is old and is prone to break down.

[toddalin]

Thanks EW

This is just making me sick. I actually bought this in Upland a few weeks ago.

Well if you need a replacement, I have one coming out of my center channel available as soon as the replacement 2420 arrives (any day now).

On another note, you may be able to remove the red seals without harm and try turing the screw. I've had the seals on my LE175's simply fall out, and I just press them back in. You may be able to get the seals out with a needle/pin with no/minimal damage.

[Titanium Dome]

At this point I'd agree with Todd. You've nothing to lose by re-torquing the bolt.

A useless driver with intact wax seals is still a useless driver.

[boputnam]

A useless driver with intact wax seals is still a useless driver.Agreed, Doug.

Only it's worse - red seals mean only that the driver has not been maintained and likely houses fatigued diaphragms (= really bad sonic quality). Get over that "red seals intact! :bouncy: " mantra once you own a vintage driver - these all need to be maintained as they are likely at-least as old as you are and will only really perform close-to-spec (and to your satisfaction... :) ) once they are properly refurbished!

[subwoof]

REMOVE the bolts that mount the horn and see what happens.

Either way a remag IS required.

Size matters

[edgewound]

REMOVE the bolts that mount the horn and see what happens.

Either way a remag IS required.

Size matters

Good observation, subwoof.

SUPERBEE...did you remove the horn at anytime and re-install? The bolts from mounting the horn can go all the way through the driver pot and push against the magnet, thereby separating the top-plate.

Whenever the magnetic circuit is broken by a top-plate separation the alnico magnet will discharge...requiring a recharge to work properly.

[scorpio]

I've had related experience with a LE85, but the plate did not separate as yours is showing, it moved sideways and slightly pinched the voice coil. I very carefully hammered it back in place (from a visual perspective) and all was back in order. I made a deal for swapping this unit to a better one very soon after that though....

[Steve Schell]

SUPERBEE, don't torque those screws quite yet. Take a look down the throat with a flashlight first. I've seen one other driver with the same apparent condition; it was also an old D-175. The throat inserts in many of the early drivers were made from an unstable pot metal, and they can deteriorate over time. I've seen the same syndrome with brackets that hold some piano actions together. The metal develops surface cracks and the entire piece begins to stretch into a new, larger shape. With pianos it can be a head scratcher, as the action looks normal yet will not remain in regulation. When this happens to a throat insert, it pushes on the pot and top plate, the top plate gives and lifts up.

If this is the case here, the driver will need to come apart for a replacement throat insert, then be reassembled and the magnet recharged. Are replacement throat inserts from JBL? I dunno. In the one I saw before, we swiped a throat out of one of my surplus rusty 2420 bodies and used it to fix the D-175. If this turns out to be the problem with your driver and you can't find a new throat, let me know.

As to the diaphragm situation, my take is a little different. Diaphragms age and eventually fail due to work hardening of the material. Aluminum has a memory and seems to remember how many times it has been bent back and forth, like a coat hanger wire. IMO one large excursion can make as much change as a billion tiny ones, so a month old pro sound diaphragm can be shot while a 60 year old hi fi diaphragm can still work like new if it has been run gently. I have heard many 70 to 80 year old diaphragms that still sound wonderful, so I would never replace a diaphragm based solely on its age. In any event, your red wax seals need to bite the dust so that you can get the driver apart.

[jerry_rig]

At least yours does not look as bad as this one (a 2441), courtesy of FedEx. The magnet has broken completely off and sheared the phenolic throat in half. If FedEx returns it (a claim has been filed), maybe someone would be interested in trying to fix it...