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New to the MG-IIIa, need help

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I just picked up a pair of late model (s/n: 0649xx and ribbons 127xx) MG-IIIas and have searched how to hook them up properly and how to evaluate the ribbons. The bass and mids seem to work fine with no buzzing using 80 wpc into 8Ω and some tones from 40-3k Hz.
I have not heard the ribbons on music of with the 3kHz tone. So I checked on and with the fuse removed, it has 0.7Ω resistance. I thought I would ask before jumping in any deeper. I figure new ribbons will be required, but help in making this determination would be nice.
Maybe it would be nice to have a list of things to do to check these out before diving into repairs. Thanks in advance.

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I'm going to listen to them now... - kff 13:44:09 10/12/06 (0)
Today was spent renewing the looks of the speakers: stands repainted, crossovers cleaned and wood nicks repaired (crossovers only none in the speakers), ALL terminals cleaned with DeOxit, fabric vacuumed (tweeter covers in place and no close vacuuming there), speaker wire washed, trimmed and terminals installed, side panels tightened. I couldn't wait to hear them some more. Tonight is gonna be fun.
So I think I have a near perfect pair including all the changes due to the later serial number, with boxes, no owner's manual (use the on-line one), no allen wrench (in the garage) and no bolts for the stands. I had 8 that fit but are 1/4" too short that work which will be replaced. Oh, two of the pipe caps on the stands are a little messed up. Glad they are on the back.
I'll worry about the wires coming unglued as the noise arises. It will make a nice winter project, if necessary.
After learning what these sound like, upgrades will be considered and undertaken.
I have an idea about the glue for the wires, possible using and SBR glue such as Seals All, Alene's Tacky glue or E6000 (thin, medium and thick). Has anyone tried any of these? I'll post this as a new thread after a search reveals no discussion for more eyes to see.
Thanks all for the info on the upgrades and such.
Re: New to the MG-IIIa, need help - neolith 07:33:07 10/12/06 (1)
The reason you are measuring 0.7 ohms across the tweeter terminals is that there is an inductor with relatively low resistance wired in parallel with the tweeter. Without going in to the math, you will essentially be measuring the resistance of the inductor and not the tweeter and even if the tweeter is fried you will measure a low resistance rather than infinity.
Before you go and remove the socks etc as suggested by AndyR, remove the little caps on the ends of the tweeter, and desolder a connection at one end. Then measure the resistance across both ends of the tweeter if you get about 2.2 ohms all is good. If you get infinity (no reading), you will have to send the tweeters back to Magnepan for new ones. You can replace the tweeters without removing the socks.
Also check that your fuses are ok with a meter- on occasion I have had a blown fuse that looked ok (at least to my presbyopic eyes).

I may be an egoist but at least I don't talk about other people.
- Never mind... - neolith 07:45:44 10/12/06 (0)
  I just read your response to AndyR and see that you got your tweeters up and running. With regards to gluing the woofer and mid wires to the panel, do a search for Peter Gunn's instructions using DAP.
  And since you will be removing the socks, consider doing some modifications: 1) Reverse the mid-bass panels (left for right and putting them in "backwards" with the magnets to the back 2) Replacing the magnepan connectors with decent 5-way posts 3) Rewiring with magnet wire 4) replacing the fuse holder with a quality unit (you probably can by-pass the mid fuse altogether with impunity but may want to keep the tweeter fuse until you are absolutely sure your amplifier does not clip), 5) look at reinforcing the MDF ala AndyR's suggestion (do a search). Eventually you will want to start working on the crossovers.
  
  I may be an egoist but at least I don't talk about other people.
Re: New to the MG-IIIa, need help - andyr 19:54:14 10/11/06 (1)
Hi kff,
First ... are you a DIY type of guy or do you prefer to have others do the tweaking work for you?
If you like to do the work yourself, I suggest the first thing you should do is take the side rails and socks off, so you can examine the mylar sheet and the wires, to see if there are OK or not. Then you can move on from there.
To remove the side rails, unscrew them; to take off Maggie's "skirt", you have to remove lots of staples on the bottom edge plus unscrew the ribbon "cage" and lift it out slightly, to enable you to get at the zillion staples in the ribbon slot! :-))
This will enable you to examine the ribbons carefully, to see whether they do in fact have any tears in them.
Then report back as to what you find ... email me direct if you like.
Regards,
Andy
PS: As a IIIa owner, you might be interested in my article in "Tweaks".
- I'm going to DIY, but I did read the manual - kff 20:19:38 10/11/06 (0)
  and found the need for jumpers. Doesn't anyone use pictures in the manuals anymore. Anyway I'll need to reglue a few sections on the woofer but the mids and tweets are now working. Thanks.

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