IMO, since the speakers aren't really "functional" in the audiophile sense and since sending to MN isn't worth the expense, you really have little risk of trying to make the diagnosis and then repair on your own. I have re-socked a pair of 1.6s and it's really not at all difficult.
First, each of the wood trim strips must carefully be removed. Use a long, but thin screwdriver and start from either end. Insert the blade of the screwdriver between the panel and (parallel to) the wood strip and very gently pry a little then push the blade further along--keep repeating. The wood strips are held in with small brads/pins and release pretty easily BUT if you pry too much when the blade is not right at each pin, you could crack or break the trim strip.
Once each trim strip is removed, you will want to pull all the brads through the wood (NOT try to push them back out the way they were originally inserted). Just grab with pliers and pull. Some brads MAY remain in the panels themselves, while others may "go" with the strips.
Next, remove all the staples from the bottom and roll the sock off the speaker. Now, you'll be able to see if the problem is visually obvious. From that point, a consultation with Magnepan might be your next best bet in terms of advice on how to repair at home. Could be a case of delamination that may be easily repairable using (and properly applying) the right kind of adhesive. Also, would ask about cure time for the adhesive, as well as an advice on surface prep. FYI, there is also some "tape" around the perimeter of speaker that might have come unstuck due to the adhesive aging so check that as well.
As far as re-assembly, the sock is probably the most difficult part (I had ordered new socks in my case--really refreshed the speakers visually). Once that's back on and stapled, you'll replace the trim strips but using NEW holes. I used a compressor and pneumatic pin nailer which made reinstallation of the trim strips a breeze, with each pin countersunk into the wood a bit. A bit of color matched fill wax to cover the new pin heads (and fill any holes from the original pins) was all that was left to make them look perfect.