Speaker Repair - UK Vintage Radio Repair and Restoration Discussion Forum

Colin Boggis · 19th Sep 2019, 12:17 pm

I don't know if this method has been used before, but I just repaired a speaker from a DAC90A with total success. The voice coil was off centre & rubbing as the fabric centring ring had come unstuck. Initially I tried to release the cone from the frame using various solvents but all I managed to do was pull off the thick cardboard trim. I then decided to take a chance and go for broke - I disconnected the 2 wires on the rear of the cone from the voice coil and then, using a sharp craft knife, cut round the perimeter of the cone. Once this was done the cone came out easily. After cleaning the frame I ran 5mm of silicone sealant right round the edge of the frame just adjacent to the fixing rim. I put a little JB weld (slow cure epoxy) round the edge of the fabric ring and then refitted the cone with 3 fine card spacers inserted between the pole piece and voice coil former, spaced at 120 degrees. I gently pressed the edges of the cone into the silicone until it sat evenly all the way round. It was the n left overnight. The next morning I removed the spacers and was pleased to fid the cone moved in & out without rubbing. I resoldered the voice coil wires and tested the speaker. Much to my surprise It works fine. So one refurbished speaker at very little cost.

unitaudio · 19th Sep 2019, 1:55 pm

Well worth the effort, old speakers aren't too thick on the ground nowadays.

Regards,
Paul

crackle · 20th Sep 2019, 8:14 pm

I have had the same fault with one of these speakers. it must be common on the DAC.
I found there was no need to remove the cone. With 3 shims inserted to centre the voice coil the cone could be pulled up leaving a gap to put glue around the rim of the inner centre ring with a fine paint brush.
Then just push the cone back down so the fabric pushes on the frame and leave overnight.
I didn't want to risk removing the fine layer of rust as it would have gone in the voice coil gap.

Mike

Colin Boggis · 21st Sep 2019, 4:38 pm

Reading the repair Crackle carried out, I think I may have gone a step to far by cutting out the cone! Good one Crackle.

crackle · 21st Sep 2019, 7:10 pm

Which ever way you do it a speaker was saved, well done.

Mike

19th Sep 2019, 12:17 pm	#1
Colin Boggis Pentode Join Date: Jun 2008 Location: Christchurch, Dorset, UK. Posts: 237	Speaker Repair I don't know if this method has been used before, but I just repaired a speaker from a DAC90A with total success. The voice coil was off centre & rubbing as the fabric centring ring had come unstuck. Initially I tried to release the cone from the frame using various solvents but all I managed to do was pull off the thick cardboard trim. I then decided to take a chance and go for broke - I disconnected the 2 wires on the rear of the cone from the voice coil and then, using a sharp craft knife, cut round the perimeter of the cone. Once this was done the cone came out easily. After cleaning the frame I ran 5mm of silicone sealant right round the edge of the frame just adjacent to the fixing rim. I put a little JB weld (slow cure epoxy) round the edge of the fabric ring and then refitted the cone with 3 fine card spacers inserted between the pole piece and voice coil former, spaced at 120 degrees. I gently pressed the edges of the cone into the silicone until it sat evenly all the way round. It was the n left overnight. The next morning I removed the spacers and was pleased to fid the cone moved in & out without rubbing. I resoldered the voice coil wires and tested the speaker. Much to my surprise It works fine. So one refurbished speaker at very little cost. Attached Thumbnails Last edited by Colin Boggis; 19th Sep 2019 at 12:19 pm. Reason: Add pictures

19th Sep 2019, 1:55 pm	#2
unitaudio Heptode Join Date: Sep 2013 Location: Manchester, UK. Posts: 862	Re: Speaker Repair Well worth the effort, old speakers aren't too thick on the ground nowadays. Regards, Paul __________________ ...No, it's not supposed to pick up the World Service, it's not a radio!

20th Sep 2019, 8:14 pm	#3
crackle Rest in Peace Join Date: Mar 2011 Location: Basildon, Essex, UK. Posts: 4,100	Re: Speaker Repair I have had the same fault with one of these speakers. it must be common on the DAC. I found there was no need to remove the cone. With 3 shims inserted to centre the voice coil the cone could be pulled up leaving a gap to put glue around the rim of the inner centre ring with a fine paint brush. Then just push the cone back down so the fabric pushes on the frame and leave overnight. I didn't want to risk removing the fine layer of rust as it would have gone in the voice coil gap. Mike

21st Sep 2019, 4:38 pm	#4
Colin Boggis Pentode Join Date: Jun 2008 Location: Christchurch, Dorset, UK. Posts: 237	Re: Speaker Repair Reading the repair Crackle carried out, I think I may have gone a step to far by cutting out the cone! Good one Crackle.

21st Sep 2019, 7:10 pm	#5
crackle Rest in Peace Join Date: Mar 2011 Location: Basildon, Essex, UK. Posts: 4,100	Re: Speaker Repair Which ever way you do it a speaker was saved, well done. Mike