Monitor 70 dust cover failure

cjq

Hello, I just purchased a pair of "70's" one of the enclosures has a problem with each speaker dust covers (excluding the tweeter) The enclosures were owned by one family member and sold by another,so, determining the cause by word of mouth isn't possible. Is it possible that the speakers were over driven and over heated? The opposite enclosure speakers have no deterioration. BOTH enclosures sound fine. There is no "cone rub".
Question, can the dust covers be replaced,is there a part number to order.
Thank you for any assistance

CJQ

dorokusai

cjq wrote: »

Hello, I just purchased a pair of "70's" one of the enclosures has a problem with each speaker dust covers (excluding the tweeter) The enclosures were owned by one family member and sold by another,so, determining the cause by word of mouth isn't possible. Is it possible that the speakers were over driven and over heated? The opposite enclosure speakers have no deterioration. BOTH enclosures sound fine. There is no "cone rub".
Question, can the dust covers be replaced,is there a part number to order.
Thank you for any assistance

CJQ

I presume you mean the center cap of the driver or speaker? It was probably caused by someone sticking their fingers in it....and if they sound fine, there's no need to replace them. Otherwise, you have to replace the entire driver which isn't cheap.

cjq

dorokusai wrote: »

I presume you mean the center cap of the driver or speaker? It was probably caused by someone sticking their fingers in it....and if they sound fine, there's no need to replace them. Otherwise, you have to replace the entire driver which isn't cheap.

Hi, your right about the center cap. Yup ,normally somebody sticks their finger where they don't belong and crush the cap. These caps appear melted. ( the caps are now flat and a bit wrinkled.)The voice coil looks like it's wound on an aluminum form so if the speakers were driven too hard and created excessive heat it took out the dust caps rather than the coil forms. They look like crap and it bug's me. But, not so much to spend money on replacing the entire drivers.

CJQ

treitz3

The drivers need to be replaced. Sorry for the bad news. Call Polk CS in the morning to see what replacements will cost.

Welcome to Club Polk.

gdb

Whoa there, new dust caps are sold all day, every day at Parts Express along with a couple other places that I can't remember at the moment.

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=260-377

they have both paper and poly caps up to 5" diameter

dorokusai

He used the word "melted" GDB.....and as mentioned, if they sound fine, dust caps don't matter.

gdb

So, some surgery might be required or, a simple "cover-up" might work well, with a better appearance as a result. A hot knife will cut plastic almost as well as it will butter.

cjq

gdb wrote: »

So, some surgery might be required or, a simple "cover-up" might work well, with a better appearance as a result. A hot knife will cut plastic almost as well as it will butter.

Thanks for the responses, I'm now at a cross road. I can obtain replacement poly cap's OR I can invest in Phase Plugs. The poly caps are the least expensive and bringthe drivers back to origional apperance. However , Phase plugs intregue me. From what I've read they enhance a drivers performance. Not sure if this is sizzle or not. I do respect those who provide technical data but don't know if my ears will hear the difference. Anyone out there have information to add?

CJQ

gdb

I am not familiar with "phase plugs".