[NostalgiaRadioTime]

Working on a 40-145 and found it has a warped / bowed speaker cone causing the radio to have a tinny sound to it. Has anyone had any luck or have any tip or trick on how to pop the speaker back down into cone shape without tearing or poking a hole in it?

   

[jerryhawthorne]

Greg, I have minimize something like that by placing the speaker face down and misting water on the cone a little at a time from the back. Once the cone is saturated it is more pliant and you may be able to gently coax it back in shape. Just something I did out of desperation and it worked. Hard to tell from the picture but it appears your surround is well attached?
Jerry

[NostalgiaRadioTime]

Thanks for the tip, Jerry. Yes, the surround is well attached, and it baffles me how the speaker got bowed out like that. Unless someone cranked the volume full blast on a strong station and blew it out! Everything else is solid...around the diameter and the center of the cone. Will take it off at some point and try misting it. For now, I put the radio back together as I have a few other projects on the work bench to tend to.

[morzh]

Looks to me like you said, someone really decided to drive the spooks out of the house and cranked the dBs.

I only saw this once, when someone plugged a movie projector speaker in a 220VAC outlet....the speaker vomited the cone right out across the room.

[Arran]

 The spider must have detached itself fro it to be pulled out like that. I would remove the speaker from the chassis first before messing with it any further. But to do this properly you will have to remove the dust cap from over top of the voice coil, then insert some plastic shims between the inside of the voice coil and the pole piece, Then with the cone dry, pop the voice coil back where is should be, but if the spider has popped loose glue it back onto the frame. Then after the glue has dried, and the voice coil is back in place, dampen the cone and put it aside to dry either facing up or facing down. No matter what you read anywhere, DO NOT USE silicone caulk for speaker repairs, this is one of those very destructive old codgers tales that does not want to die for some reason. One more thing, if you don't think you can handle fine detail work pass the speaker onto someone who can.
Regards
Arran

[jerryhawthorne]

Arran certainly has much more experience than I do Greg. Indeed the cone may be separated from the voice coil and hard to tell from the pictures. A great idea to carefully remove the dust cover and review that situation. Spacers should work well around it if you need to re-attach the cone with some adhesive to the voice coil. I would not try to manipulate the cone manually with it dry. Look carefully at the spider as well as suggested, if loose not bad to re-attach, nasty if it is broken.
Best, Jerry

[NostalgiaRadioTime]

Thanks very much Arran. I will investigate it further. The spider may very well have detached itself and I just didn't notice. I didn't do a lot of poking around on it because I know all too well how fragile these cones can be. Another theory on what happened to it could be damage in shipping; that the radio took a hard drop face down. But if that was the case I would have expected to see cabinet damage too, which I didn't. I think the full volume theory may be the most likely culprit.

[BrendaAnnD]

Looks like peanut damage to me.

[NostalgiaRadioTime]

The radio had a full back on it in shipping so there were no peanuts inside, but good thought!