Refoaming Philips FB-561 woofers
The same woofers are being used in the FB-563 and FB-565.

The FB-561 contains a very special woofer, just like the other speaker from Philips' Digital World Series. It's not just that the foam ring is glued under  the speaker cone, the rings has also been mounted inverted! We decided to repair this woofer with a new foam ring. We glued the ring behind the speaker cone as well  but chose not to mount it inverted. A report........

 

 

Here you can see the woofer the way we bought it. The ring seems fine, but you can see a small hole. Also you can see a small 'dent' in the ring on the left side. These are signs the ring is lost!
The woofer is mounted behind a plastic gasket, we have te remove it to see the whole of the woofer. You can clearly see the inverted ring, glued to the back of the cone.

 

 Re move the speaker from the cabinet. Note the paper and foam rings that seal of the woofer. These foam seal-rings can be re-used most of the time because they didn't suffer light, oxygen and smoke during the last 20 years.

 

Remove the wires - don't solder to hot or to long. You can damage several parts if you do. Work precise and quick and don't use more heat than neccessary. Mark the cables, so you know how to attach them once your finished. Please note most speakers have a marked (red) connector; that's the plus (+).

 

Here's the woofer. You can clearly see:

  • Hole in the foamring
  • Inverted foam ring
  • foam ring mounted behind the speaker cone

On the background the foam sealing ring that will de re-used.

 

 The easy part..... Tear of the old ring. Remove as much as you can. Please note the units lies on an old newpaper bacause the old foam is nasty stuff that can ruin your clothes of table cover.

 

 Less easy: remove the old foam ring from the back of the cone. It's most easily done by 'rubbing' your finger gently over the cone, moving towards the edge of the cone. Again: remove as much as you can. Sometimes you can 'tear' a part, or even a whole ring, then you're lucky!

 

 The old ring is gone, it's time to clean the frame. It has to be as clean as possible. Here we use a small spoon to rubb off the debris. You can use other tools if you want.
Don't use to much force. Make sure the frame is 100% clean. You can remove the final parsts of the glue with a cotton dipped in alcohol or thinner. We finish this part by using some ammonia to remove the last grease.

 

This is where the alcohol and later the ammonia comes in......

 

 OK, both frame and cone are clean. Of course you have folded the ring around the cone once to see whether it fits.......
Now it's time to glue the new ring to the cone. Spread our special glue over the inner flip of the ring. Spread so much the glue remains white and liquid. On the parts you added to little glue the glue will dry instantly - add some glue to those parts. Don't use too much, but obey the rule about liquity and colour.

 

'Fold' the ring behind the cone. Our special glue gives you plenty of time to do it right, so don't hurry. You can use a 'tool', i.e. a knive, to lift the cone a little in case it's hard.
Once the ring is folded behind the cone, gently push the cone a few times. Let the glue dry for a few hours. You might want to put some weight on the unit.

 

Here's another way to glue to the cone: fold the ring behind the cone and lift the cone a little. Spread the glue on the inner flip of the ring and work your way around. The rule about the amount of glue is the same: it must look white and liquid.

 

 I have put some weight on the speaker cone, not to much. Maybe a 150 gr. or so. Note the bottle with our special glue.

 

Some woofers have holes in them that are not totally flat around them. I recommend to cut the ring on those spots, so you can glue the outer part of the ring to the frame more easily.
You cut the holes? OK.Now lift the ring with a knive and put the glue on the frame. Work you way around. Then gently push the speaker cone inwards a few time to 'center' the voice coil. If you glue the ring to the back of the cone the speaker will have a strong tendency to 'auto-center', so little correction will be neccessarry at the most........

 

 I've soldered the wires to on the speaker terminal, have put the foam seal ring under the woofer and tightened the screws.......
The final result........

Good luck with repairing your speakers!