replace foam on apm 177-m : need help ...

[eggon]

Hi everybody .

Finally 5 years after my first post , i ordered a 2 suspensions set tor replace those from my APM 177-m; it's been provided by the guy from Moscow wich sell these on ebay.

For those wich have already succeed that repair, i've got a few questions:

1° as you can see on this picture, there's some old dry glue on the sides off the honeycomb : is there any safe way to remove it before replacing the new suspension ? Im scared
to spoil it .



2°) Consider putting on the new suspension, how i am suppose to process ? has shown on next photo, the replacement part is full in its center . If I need to cut the inside ,
what size should the inner border be ?



Any kind of help will be appreciated

thanks

Eggon

 

[Superduper]

I'm no expert here, but if those were my speakers, I would leave the glue residue alone. If you look at the Sony speakers when the surrounds were intact, and you peek carefully through the grill, you'll probably find that the amber glue is actually visible anyway and messing with it will probably damage the fragile cone surface.

As for the surround, I would probably glue the flap on the backside of the cone. It is going to be very difficult to cut the surround and end up with an attractive edge that follows the contours of the cone properly. Depending on the location of the "hump" and whether it will fit facing forward or backward (you will need to test fit), it may be that the concave side will have to face forward leaving the cone surface to define the visible edge. Not sure why the interior edge of the surround is not already cut out for you, but I suspect that the seller tried and decided that he could not make accurate cuts that looks attractive, and therefore affect sale-ability after cutting. In any event, if installing by glueing on the backside, then the overlap can be whatever you feel comfortable with and have room for. Obviously, a larger overlap will be easier to glue than a very thin one.

 

[eggon]

I'm no expert here, but if those were my speakers, I would leave the glue residue alone. If you look at the Sony speakers when the surrounds were intact, and you peek carefully through the grill, you'll probably find that the amber glue is actually visible anyway and messing with it will probably damage the fragile cone surface.

As for the surround, I would probably glue the flap on the backside of the cone. It is going to be very difficult to cut the surround and end up with an attractive edge that follows the contours of the cone properly. Depending on the location of the "hump" and whether it will fit facing forward or backward (you will need to test fit), it may be that the concave side will have to face forward leaving the cone surface to define the visible edge. Not sure why the interior edge of the surround is not already cut out for you, but I suspect that the seller tried and decided that he could not make accurate cuts that looks attractive, and therefore affect sale-ability after cutting. In any event, if installing by glueing on the backside, then the overlap can be whatever you feel comfortable with and have room for. Obviously, a larger overlap will be easier to glue than a very thin one.

Thanks for your advices; concerning the glue residue, i've seen on another site, that a guy has successfully remove it with nail lacquer thinner (one with no remover) but you probably right , its to tricky et the honeycomb is too fragile , so i will probably let it as is.

For the surround, i'm not sure at all that the global size off the foam suspension will allow to glue it by the back side of the cone . I think i will try first with a piece of paper or light cardboard and trim and adjust till it fit ; if it's successful, maybe i could use it a as a template .

As i said above , i found other sites on how to reply APM suspensions. I'm not 100 % sure but it seem on the last photos that the suspension is glued on the top of the cone , first glued on the center on the cone then after adjustement , on the sides of speaker :

Sony APM-550 - suspensions HS - vintage-audio-laser.fr

Anyway, i wil try and let you know how i did it ..