How to tell if EMIM or EmIT drivers are in trouble

Hi all,

I am considering buying a used pair of Infinity Renaissance 90s. But I am concerned about the EMIM and EMIT planar drivers. They sound good, but they are reputed to be fragile and to deteriorate with time, and I notice on both of the EMIM's that the diaphragm is slightly bulging/bubbling (maybe a couple oval spots 2-3mm long). I that a sign? Are they likely to give up sometime in teh near future anyway? I am very reluctant to buy them because of the impossibility of replacing the midrange and tweeters if they go. Any words of wisdom, please, you who know?

I owned an Infinity RSIIa for 17 years.

The main #1 problem of any EMIM or EMIT is the tabs the wires connect to break off from fatigue.
Which renders the driver inoperable. The tab is either good or cracked. Most cracked ones do not last long. and you may find solder blobs in the tab base.. Which means the tab was broken, or half broken off.
The crack would be right where the speaker electrical wire push tab enters the rectangular base.
For awhile this was a serious problem as no EMIM inserts were available. But then an Australian company made some (I think they are no longer making them??? patent rights? Anyway. that is the #1 fault. And it is a killer. Fixing them is possible, but really a mess to do. Soldering a wire directly to the cracked off area?? Or takingthe EMIM apart and adding a makeshift tab/trying to electrically getting it attached to the EMIM inner contacts. (You would need to make a 'jig' so the EMIM could be reassembled. The magnets are a PITA to align!!

Anyway, for the actual EMIM driver surface. The bubbles and all mean nothing. Most EMIM and EMIT had Scotch tape applied (or some other clear adhesive backed tape) and invariabley it had some ugly looking long ovid bubbles under it. No problem at all. The metal film is very thick, and I never heard of anyone having trouble with it breaking or separating in any meaningful (audible) way.
So IMO the drivers appearance with lumps or cloudyness or bubbles under the film means nothing. As long as the metal parts under the tape do not look black, or seriously discolored..They should still be shiny aluminum looking under the tape.
Being whitish/cloudy from the tape is no problem.

So that is my experience with My own Infinity with three EMIM and three EMIT per side.

A broken EMIM is expensive to replace, as only used ones around and those rare. I took my speakers apart and sold the EMIM for $200 each which was a bargain for the buyers who needed them to fix speakers..

The solution to cracked tabs is: If the speakers are old and NO cracked off wire connection tabs LEAVE IT ALONE !!! that is good news.
When you do have cracked tabs.. the big thing is to stop them from vibrating Soldering to strengthen the tab is OK. Some redressing of cables (again ONLY if they were bad) would be in order to relieve stress on the wire tab interface. And some putty, like Blutack a bit of it on the connection to stop it from vibrating.
I'm thinking of replacing my Emit R tweets with another set...or a modern Morel mdt 29 for half the cost...and recommended at my reputable, regional speaker repair shop...any tt thoughts?