Martin Logan ESL Expression 13a amp removal, woofer not working

Your woofer cone may be intermittent. Rather than examining the amp, first swap the drivers, see if the problem moves with it.

There are a couple of places where this can happen. The solder to the connectors/tabs can become loose, but the wiring that goes from the tabs to the coil can become lose. The glue can come detached and/or the solder that connects the flexible wires from the tabs to the voice coil wires can fail.

Fortunately this is a case where a simple continuity tester from a multi-meter will help.  If in doubt, hook it up and gently play with the wires see if the resistance or continuity changes.

Call Ron, in service, at ML.  Have your serial number handy.  He is great to work with.

Great thoughts. I was just wondering if this sounds like a common "oh yeah, that's always this fuse, replace and be happy."  

I'll swap the woofers in a bit and see what happens. 

Ok, I swapped the woofers, same thing.. Rear woofer is out and seems to be an amp problem.. Hmm, I'd much rather replace a woofer than take the amp out and send to ML.  

Of course, I would discover this on a holiday weekend and I'm sure Ron at ML will be slammed on Tuesday.