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Wagner
08-12-2015, 09:18 PM
I am in the process of finishing up some fine points on a very clean pair of L100s

Today I removed all of the drivers in order to do some cosmetic work on the front baffle and to do a re-cap

I am fortunate in that I have all of the original drivers and my LE25s work and measure fine, as do the mids and woofers

My concern is that today I noticed for the first time since I've owned this pair that the festons (the actual spades, both male and female) can move; the females more than the males

Not floppy loose, but still not tight; I noticed this while disconnecting the hook up wires

The amount of movement is the same on both tweeters and the actual brass rivet which attaches the lug does not move at all, i.e.: this "condition" is consistent with both examples

I personally have never actually seen how the VC's lead wires attach on the other side (at least that I can remember anyway)

They measure well DCR wise and I cannot induce any open circuits with gentle manipulation.................still, this cannot be an ideal situation as far as the ultimate connection integrity goes...............or is this normal and I'm just now seeing it?

I am not looking for a problem that's not there, but I cannot tighten that rivet without removing the diffuser foam and both units have new foam that was installed when I first acquired the speakers (and I'd like to avoid destroying it as well as the fact that I do not currently have a spare set on hand)

I am thinking about a quick surgical tack job with the soldering iron (I'd feel better about it) but you all know the risks with that

I cannot find any exploded views of the LE25 or any comments on line regarding this phenomena

Is this normal or should I do something to tighten things up? I'd like for this session to be the last time I open these boxes up, at least in my lifetime

Anyone who has handled these old tweets on the "all apart" level who would be willing to comment would be greatly appreciated

Thanks to all

grumpy
08-13-2015, 07:06 AM
Lots of pics w/o foam if you google LE25 images.

or about 1/2 way down here: http://www.troelsgravesen.dk/JBL_L100_08.htm

Unless the faston connector continues through the hole behind the rivet, -seems-
like a loose terminal in this case would be non-preferred.

Other faston connections often use a rivet just to hold the connector to a tag board
and the connector itself is soldered to (VC or tinsel wire), so a loose rivet isn't a
huge deal.

Not a definitive answer, but I hope it helps somewhat... I don't have a dead one
to disassemble or I would.

Wagner
08-13-2015, 08:05 AM
Lots of pics w/o foam if you google LE25 images.

or about 1/2 way down here: http://www.troelsgravesen.dk/JBL_L100_08.htm

Unless the faston connector continues through the hole behind the rivet, -seems-
like a loose terminal in this case would be non-preferred.

Other faston connections often use a rivet just to hold the connector to a tag board
and the connector itself is soldered to (VC or tinsel wire), so a loose rivet isn't a
huge deal.

Not a definitive answer, but I hope it helps somewhat... I don't have a dead one
to disassemble or I would.
I saw those too, thanks
What I've got and what I can (barely) remember) before I replaced the diffusers:
Front of tweeter my voice coil wires to the silver spot ("silver" from the solder?), "OK"
Back side of tweeter, a brass colored rivet head (smooth) holding the brass male or female feston spade(s) (I have always assumed just the other side/end of the same piece of metal the VC wire is soldered to)
It's those spades that will move with a minimum of pressure (like disconnecting wires, even if you are careful and use the right tool)
Just encountered a similar situation with a tag board riveted to one of those old Telefunkens I am working on; on one driver there was continuity through the rivet to the frame, on the other, 50 years had created an open circuit situation
This rivet also was through a spade lug for the purposes of connecting circuits (wires) but all of the solder type, i.e.: a terminal strip construction
Fortunately in that case it didn't involve signal, was just a coincidence that I noted during inspection (Telefunken uses those tags to tie wires and caps) I eliminated the use of them and installed the caps in a traditional "American" manner
Point being, now I am concerned because I have just recently held in my hands a "not so tight" rivet, from the factory, "go open circuit" on me

There is clear and easy access to those festons and their attaching rivets on the LE25, so tacking with a hot iron is an easy enough task )I have improved these sort of compression joints before on numerous old projects

I just do not know with certainty HOW the VC wire "connects" to that solder spot; is it through a hole or involving any sort of mechanical holding before solder is applied or just lying on the surface (like an SMD joint) Obviously I'd like to avoid "un-soldering" it in order to tack my festons in place! :)

My new diffusers are ON as in really really ON there (installed 2009, REAL GOOD PRESSURE SENSITIVE ADHESIVE, I'll tell 'ya that! :)), so removing them is not a desirable option and as I mentioned I don't have a spare pair lying around; the adhesive being so effective I probably would break those leads now after they've managed to survive 40 years!

I spent an hour searching LE25 repairs last night and could not find one clear shot or example of how they actually effect that damn connection (and clearly I have never had one apart or had to do one myself) I've only cleaned off the old adhesive and stuck on new foams and have just seen that silver "dot"