This explains how to install new tweeters and fix the mid/base panels on your magneplanar speakers (corroded wires and mylar damage)
There may be better ways to do some of these tasks, and if anyone has a better way, feel free to add to this.
I have done Tympani's, MGI's, MGI Improved, MGII's, and SMGa's this way, however, these methods can be used on all the magnepan models. ( However, the information does not cover ribbon or quasiribbon replacement)
The repair will take anywhere from 3 hours per speaker to install new tweeters, and up to 2 - 5 hours per speaker for the mid/base panel for lifting wires, mylar damage, and/or corroded wires.
After removing the socks inspect the surface of the speaker.
Usually you will see some of the ends of the mid/base wires lifting, and sometimes in the middle of the speaker (especially where the mylar is held down in the middle of the panel, for proper frequency response - in these areas it may appear that the wires are stretched and appear that they are too long to lay down flat, in which case I curve the wires back and forth laterally until I figure the wires will glue down properly.) The most important thing is that the wires are held against the mylar everywhere, not that the wires are uniformly spaced apart.
The 2 biggest problems with the speakers that will make them virtually unrepairable is when the mylar damage is quite extensive in one area ( a large tear so the mylar is no longer tight side to side ) as long as the mylar damage is not too extensive in one spot, and the mid/base wires do not have too much corrosion of the wirethe speakers can be repaired with some work. These wires will corrode over time, and especially if left in damp areas over the years.
How to repair corroded mid/bass wires.
If the wires are corroded at the end of the speaker, just lift that wire, cut off the corroded section, strip the coating off each wire (razorblade), and then you can either solder the wires together, or as I did (just so you don't risk damaging the mylar more with hot solder, is get some of the small wire connectors from radio shack (the small ones are red, but ask for, or find the ones that have no plastic coating, just metal; use some good wire cutters to spread them apart, and use pliers to flatten the thing. Use the wire cutters to cut a narrow strip of the metal (make sure it doesn't fly across the room when you cut it). Bend the strip back into an arc shape (trim it shorter if you want. Now crimp the metal over the two ends of the exposed wire (be careful not to twist or pull the wires much, the metal is fairly soft and will break if you twist it much)
If the wires are corroded in the middle of the speaker, you would be best to call magnepan and order some mid/base wire for your speaker when you order a tweeter kit. ( If you are not sure how badly corroded your wire looks on the surface, if the coating on the wire is raised and looks suspect, in an area longer than half an inch, then there is a good chance either now or in the next few years you will need to repair those areas( but I guess 'if it ain't broke don't fix it' would apply here), so I recommend ordering some wire now (it's not much to buy), and if you're paying your $12 shipping anyway (which is what they charge), you may as well get some.
If you plan to use the silver solder and flux, you can, but it is more risky here. If you put cardboard in between the wires and the mylar to prevent the heat from melting the mylar, and lift 2 inches of wire on either side of the area you are soldering ( the wires get hot and could melt throught the mylar), and make sure your solder when in liquid state, does not roll off your surface onto the mylar ( I am speaking from hard earned experience here ). The thing I found difficult was even with flux, to get good contact and strength you will need to get solder around the wires like a donut ( I found this very difficult, even with flux ). I only recommend using solder for the mid/base wires if you have some experience with solder, otherwise, I recommend the method listed above. You'll need silver solder and flux.
How to repair damaged mylar.
If you have some mylar issues, move the wires out of the way, clean the area with acetone & paper towel, spray the glue on something like a peice of paper or cardboard, dab a toothpick or something in the glue, and paint a little glue on the mylar around the hole/tear (make sure not to get any glue at the edge of the hole - be conservative with the glue here, you do not want any glue that will cause that when finished, will cause the mylar surface to want to stick to the magnet strips on the other side of the speaker (this will highly affect the sound. If you mess up, just acetone the area, and start over) Take a piece of scotch tape, cut it just big enough to cover the hole/tear, and use tweezers to lay the piece of tape down GLUE SIDE UP ( the glue you wiped on the mylar will hold the small piece of tape down) Now take a larger piece of tape and just lay the tape over the other piece, this time with the glue side down against the mylar.
How to attach lifting wires.
Note: If you have the older magnepans, say tympani's, MGI, MGII, MGIII, the glue used on these can be effectively softened with some acetone. If you have wires lifting in the middle of the panels, just lay the speaker down, sparingly pour acetone on the speaker surface, wipe off excess acetone, and then use weights ( I used sockets from a socket set) to hold the area down as the glue drys (the glue will become tacky enough to hold the wires down; if you wipe off to much of the original glue in some areas, just spray some of the Super 77 spray glue on that area & wipe off the excess, and keep going).
Use 3M Super 77 spray glue (the big bottle at home depot is $8.50). Also, get 1 quart/liter bottle of acetone to remove excess glue. Cover areas not being repaired (protect against overspray), lift the wire/wires to spray the mylar underneath (use something to hold the wires away from the mylar (slide something under them (small screws)/use tweezers), spray the glue at angles so the glue is sure to be in the area under where the wires will lay down. As soon as you spray the glue, you will want to have a paper towel to gently wipe the off excess glue from between the wires after you lay them down be sure not to take off to much glue, the wires still have to stick. If there is visible glue between the wires ( or at least too much, it will not allow the mylar to move as freely, and would diminish the quality of the sound) you only have a good 10 seconds here before the glue will gel and you will need acetone to get it off after that. I used a whole bunch of sockets from a socket set to hold the wires down (make sure you rotate them as the glue dries (do not lift them or the wires will come back up with the glue/socket) The advantage of using something metal is the sockets are held down not just by their weight, but also the magnets hold them down (strips of magnets are on the other side of the mylar).
Keep rotating the sockets, and after an hour (for the middle of the panels) and say 2 - 3 hours for the ends (due to the extra glue used here), you can remove the weights ( by rotating them back and forth - do not lift the weights or the wires will come with it) You can remove the glue off the sockets or other weights if you don't want glue all over them, by just using acetone and papertowel or old socks.
I recommend doing the body of the speaker first, leaving the 2 inches at each end until the rest of the wires are glued down. At this point, the ends require more glue and a little more weight to hold them down. Just remember to wipe off excess glue before it starts to gel. If you don't get it off now, if you are careful, you can do it after it dries by using acetone on papertowel / old socks)Wear gloves (changing them often), and get a respirator, or do it under good ventilation.
How to install new tweeters.
How do the tweeters sound / look. If good fuses don't change the sound when you remove/install them, you have a bad tweeter(s). You can order the tweeter kit which will give you all the wire you will need, and the UV protectant which you will need anyway (I think it's $30 per pair of speakers). Take a piece of wood (pick it up when your at home depot getting the other stuff)about 1.5 - 2 inches wide and say 1 inch thick. Have them cut it to just under the length of your speaker, say 45 inches. Buy 7 4 - 6 inch bolts at the same diameter as needed to wrap the wires around ( You need 3 at one end, and then 2 to make up the other end of the tweeter, but on either side of those a little farther out, you will need to wrap the wires around these to hold the wires tight to wrap the wires around, and lay down the wires. Before you drill the holls for the bolts, make sure you have them spaced at the correct distance appart (width and length)You will also need 2, 3 inch flat head screws to screw in a little, on the same side as the wires, and right in the middle of the wood template. Screw them in just enough to be below the level of where the wires will pass by when you string them around the template. You need these screws to prevent the wires rom sticking together when you spray them with glue.
I also used some thin solid wire to wrap around the bolts to keep them evenly spaced and to keep them form sliding around too much (make sure you can still rotate them without too much trouble, but with some tention)Oh, and make sure the thread on the bolt is on the side where the wires will be strung.
Now after the template is all put together, start from one end, at the tip of the bolt's threads, wrap the wire around a few times, and string the wire back and forth, from bolt to bolt, until you are at the last bolt, and them wrap the wire around this last bolt. Make sure you have enough tention to keep the wire tight ( it will keep stretching on you too).
Spray the glue back and forth on the side of the wires that will touch the mylar.
Note: Make sure to clean off all glue and old wires from the tweeter area with acetone before you get to this point.
Now there is no big rush to get the wires layed down after you spray them. You have about 20 minutes or more of working time after you spray the wires.
Even if the wires stick together or even if the wires come off the template and they are all stuck together, just take your time and separate them by sliding something between the sticky wires, and slowly re-string the template, spray a little more glue on the wires, and keep going.
Line up one wire at a time, and carefully press it down along its length, if it's not completely lined up, you could try to lift it up, and reapply it to the mylar. It is not critical that the wires are perfectly spaced, nor that the lines are perfectly straight, but do your best.
The reason for the template is to use the least amount of glue, but yet have good adhesion of the wires to the mylar.
After the wires are stuck against the mylar, have your acetone handy, and wet an old sock or some paper towel good, and hold it against the bolt you are trying to remove the wire from ( at this point the glue is very tacky and will not want to come away from the bolt's threads - hense the acetone). Rotate the bolt counterclockwise slowly and use some tweezers to gently separate the wire from the bolt as you rotate it ( You can do this all yourself, just take your time and don't worry about the glue drying on you).
Spray a some glue down on the mylar at the ends; give it at least 30 seconds to become tacky, and then press the wires down. They should stay down on their own ( not like the mid/base wires ). Press the wires down with your fingers to make sure they are glued down good, and that's it.
After it all drys, solder the ends of the tweeter wire to the corresponding terminal ( or a piece of the wire coming from it ).
Note: Make sure you strip the wires with a razor blade to remove the coating to get good contact. Solder the wires using flux, and then test the tweeters for sound by using removing the fuse and then replacing it, or if you model hase no fuse, just compare it before you soldered the tweeter wire, and then after. I had my speaker going at low volume as I soldered my tweeter, and you can hear the speaker cut in and out as you get good contact.
Now test the speaker at moderate volumes to make sure there is NO buzzing sound (wires not attached). If you still have buzzing, carefully inspect the speakers for areas yet not attached, and refer to the section on attaching the wires.
I gave my speakers a few days of testing before I added the UV protectant.
Now apply the Myloxane that Magnepan sent you ( UV protectant ). Paint it on the areas worked on (use it sparingly).
Let it dry, and now you are done.
I have done 5 pairs this way, and it has worked very well.
If this all sounds like a lot of work, it is.
This post is made possible by the generous support of people like you and our sponsors:
Topic - Magnepan Repair Explained - Compreh - Alex 12:08:38 10/08/02 (1)
- Re: Magnepan Repair Explained - Compreh - Leisure7 15:15:56 10/09/02 (0)
You can not post to an archived thread.