Quad ESL 57 treble cell reparation

The total area burned away from the arc damage is tiny compared to the entire radiating area. The difference is smaller than the manufacturing tolerances of those panels. So NO, I would suggest only scraping away the burned area (so that it's farther away than the normal spacing), and then insulating the area.

Sheldon
 
I have considered doing that in the past, you can buy a spray conformal coating that dries quite thin. But I never do that, I locally insulate damage after minimizing it with corona dope, but leave the rest of the panel just as quad made it. I also install treble panel protection clamps so damage is much less likely in the future.

Sheldon
 
Related to this topic ... is there a solution which could be applied to the mylar by opening the panel and paint on ? I did some work many years ago, opening the panel to fix some arching burns and isolate them. Now I kind of dislike the very slow charging, so maybe things are different now and it can be fixed by a better solution ( fluid, graphite or similar) ?
 
And how would you wipe off the Nylon coating without breaking the Mylar?
Additionally:
- Be sure everything is off
- Be sure not only not to tear the Mylar, but don't mess with it's structure
- Be sure to keep tension intact and not push over the stretch limit at some point
And maybe more
 
I hear you, yes the big risk is that the mylar does not adhere to the stator when disassembled. I know it nearly happened to me, but I was lucky only one corner split. This was easily fixed by some epoxy.

I was thinking one could apply some solution to the mylar in some pattern to connect the isolated parts of the mylar.
 
That will work in most places, but not round the holes.
Round the holes the Mylar and coating film are melted together by making the holes with a soldering iron.
In my efforts to remove the Nylon film and leave the Mylar in tact, it always ripped there.
It is a complete fusion of 2 materials around the holes.
 
The chances of damaging the diaphragm during splitting the speaker is pretty high. And what is the point of saving a little mylar? put a new diaphragm in it while you are there. In my limited experience, the mylar in the treble panels is pretty well stuck to the stator at the perimeter where it should be. But it's often pretty well stuck down the center as well and will often tear when separating the stators. That said, I'm never very gentle with splitting the panels because I take a scorched earth stance, with the expectation that the diaphragm and its silly coating will be removed.

Sheldon