Drivers not working right

Easy Runnin

I just acquired a pair of monitor 7bs that need some tlc. They do not sound very good. I took the drivers out and one must be miss wired. On one the white wire is attached to the terminal with the red mark. On the other, the black wire is connected to the terminal with the red mark. Which is the right way? If I'm not mistakes, black is positive and white is negative. correct? What about the driver? Does the red dot mean negative? Also, is there a way to test the drivers?

thanks for the help

F1nut

If I'm not mistakes, black is positive and white is negative. correct?

Correct.

Does the red dot mean negative?

No, it means positive.

Easy Runnin

Thank you. How do I know the 6500 s are good? If i'm not mistaken, i got 6.7 and 6.5 ohms, when I pushed on them with my fingers there was very little movement but there was no scratchy sound. Would it be ok to just connect speaker wire from the receiver to each one?

westmassguy

Easy Runnin wrote: »

Thank you. How do I know the 6500 s are good? If i'm not mistaken, i got 6.7 and 6.5 ohms, when I pushed on them with my fingers there was very little movement but there was no scratchy sound. Would it be ok to just connect speaker wire from the receiver to each one?

All the MW6*** Series drives should move in and out freely. You may have magnet shift, which has "frozen" the drivers in place.

Easy Runnin

Ok I believe both drivers suffer from magnet shift. Tonight I cleaned things up a little & hooked everything up right. The one driver makes noise and might be worth trying to fix. The other makes no sound at all. I got 6.5 ohms on the one that makes noise and 10.8 ohms on the one that doesn't. The surround on quite one is flat as well. This guy is pretty much worthless, would you agree?

Do you think it would be worth wild to use the dead one to pratice fixing the magnet? Any other advise?

westmassguy

Easy Runnin wrote: »

Ok I believe both drivers suffer from magnet shift. Tonight I cleaned things up a little & hooked everything up right. The one driver makes noise and might be worth trying to fix. The other makes no sound at all. I got 6.5 ohms on the one that makes noise and 10.8 ohms on the one that doesn't. The surround on quite one is flat as well. This guy is pretty much worthless, would you agree?

Do you think it would be worth wild to use the dead one to pratice fixing the magnet? Any other advise?

If you do a search of the forum, there are a couple members who built some special jigs to re-center the magnets. One was made inexpensively out of PVC with some threaded bolts as I recall. I had one frozen driver last year that I re-centered a bit differently, but I re-edge and re-cone speakers for a living, so it wasn't that big a deal for me. I don't know the physical condition of the speakers, what you have into them thus far, or how much you're willing to invest to get them functioning again. You can check eBay for a working replacement pair. I believe Polk sells new replacements for $48.00 each as long as you're a Club Polk member.

Easy Runnin

These speakers are fair at best. I have a total of $20 invested in them. They do have the peerless tweeters. At this point I don?t think I want to invest too much money into them. I have no experience in this area but I am interested in learning more. I did find the posts you were referring to.
My thought process is since I really have nothing to lose, I would like to try to fix the magnets. I figured if the one driver is totally trashed I would start with that one in order to get a feel for things. If it seems manageable after that I would attempt to get the other driver working. If it works I can get a better idea of how the XOs and tweets function. And then figure out what to do next.
At this point, based on my lack of experience I assume the one is trash but I don?t know for sure. I would probable handle the attempted repair differently if I knew it was fixable. Would you agree the driver is trash? If not, what steps or precautions should I be concerned with as I proceed?
Thanks for any advise.

westmassguy

Easy Runnin wrote: »

These speakers are fair at best. I have a total of $20 invested in them. They do have the peerless tweeters. At this point I don?t think I want to invest too much money into them. I have no experience in this area but I am interested in learning more. I did find the posts you were referring to.
My thought process is since I really have nothing to lose, I would like to try to fix the magnets. I figured if the one driver is totally trashed I would start with that one in order to get a feel for things. If it seems manageable after that I would attempt to get the other driver working. If it works I can get a better idea of how the XOs and tweets function. And then figure out what to do next.
At this point, based on my lack of experience I assume the one is trash but I don?t know for sure. I would probable handle the attempted repair differently if I knew it was fixable. Would you agree the driver is trash? If not, what steps or precautions should I be concerned with as I proceed?
Thanks for any advise.

That's a hard question to answer. If they were mine, I'd certainly attempt to repair them, but I also have experience reconing woofers and centering voice coils etc. The last one I did, was fully locked in place. I cut the dust cap, inserted voice coil shims in the air gap, and GENTLY tapped the magnet back into place. This took a few tries, but after 15 min or so I had it centered, and immediately glued the magnet. Not sure if you're willing to attempt that type of repair.

Easy Runnin

Well I attempted the repair. You made it sound easy. Not so for me. Damaged the vc on the first attempt. I cut the dust cap but couldn't get anything to move. Tried to push the back plate off through the air gap and vc stayed with the poll as it came out! I don't think that one was going to be repairable anyway. Couldn't get the second one to move either but I was able to get it apart with no apparent damage to the vc. Going to try making a jig for reassembly. How would you glue it? Should I apply between plates or could I just run a bead around the seems? I have some west systems expoxy left over from a previous marine project. Do you think that would be a good choice?

F1nut

You can't beat West Systems epoxy.

westmassguy

Easy Runnin wrote: »

Well I attempted the repair. You made it sound easy. Not so for me. Damaged the vc on the first attempt. I cut the dust cap but couldn't get anything to move. Tried to push the back plate off through the air gap and vc stayed with the poll as it came out! I don't think that one was going to be repairable anyway. Couldn't get the second one to move either but I was able to get it apart with no apparent damage to the vc. Going to try making a jig for reassembly. How would you glue it? Should I apply between plates or could I just run a bead around the seems? I have some west systems expoxy left over from a previous marine project. Do you think that would be a good choice?

Easy for me because I do it for a living. If F1nut says you can use it, use it. Don't need to get fancy with the epoxy, just run a bead around where the magnet meets the back plate

Easy Runnin

Success! At least I think so. I made a few mistakes but I think I'm ok. First mistake, I dropped a magnet and broke it. No biggie because the first drive was trash. Next I made a jig assuming I would glue the magnet to the back plate first. Then I went and glued the magnet to the front plate. After modifying the jig I reassemble and start finer tuning. I can' get it just right. I still here scratching when I push on the cone. So without gluing I decide to drop it in the speaker to hear how it sounds. The first speaker sounds good to me. Next I carefully move it to the other speaker and this one sounds good also. Next I push on the cone, it moves freely and I do not hear any scratching.

Now I just removed it from the speaker, and I'm going to thicken up some epoxy and run it around the edge where the speaker and backing plate meet.

westmassguy

Congrats

Easy Runnin

Now tell me what you think of the tweeters. I'm pretty sure they are the desirable peerless tweeters. The number on the back is 55141083. Should I be concerned with the wrinkles in the black domes? Any other issues to be concerned with?

Thanks again

westmassguy

Easy Runnin wrote: »

Now tell me what you think of the tweeters. I'm pretty sure they are the desirable peerless tweeters. The number on the back is 55141083. Should I be concerned with the wrinkles in the black domes? Any other issues to be concerned with?

Thanks again

I've seen worse. Unfortunately there's no was to pull out the wrinkles on the dome without risking ripping the dome right off. The Peerless are on eBay all the time.

Easy Runnin

The wrinkles won't affect the sound. Will they?

westmassguy

Easy Runnin wrote: »

The wrinkles won't affect the sound. Will they?

I'm sure if you had extremely accurate measuring equipment, there might be deviation in the sound radiation pattern, on axis/off axis. If the sound good, just enjoy them.