Rogers LS35a/5a troubleshooting

[DavidRowe]

Hi everyone, I found a pair of LS3/5A’s in my workshop that someone gifted me years ago. I had no idea what I was sitting on till recently. After giving them a wipe down and plugging them in I have discovered one of the speakers (so12882B) is very quiet. I opened it up to take a look and found the b110 drive units rear magnet part had been dislodged. I have put it back in place but they are still very quiet.
I know there are some experts on here and was hoping you could guide me in diagnosing the problem. I’m definitely a novice, any help is much appreciated
Cheers
David - Wellington NZ

 

[absolve2525]

Dang, sorry you have to deal with that! I bought these replacements from Falcon that sound identical (to my ears). Same tooling and materials as the originals. I would check solder joints and make sure resistors aren't burnt or out of spec. https://www.falconacoustics.co.uk/falcon-b110-8-ohm-kef-b110-sp1003-replacement-pair.html

 

[A400]

I opened it up to take a look and found the b110 drive units rear magnet part had been dislodged. I have put it back in place but they are still very quiet.

Hello fellow Wellingtonian.

If the magnet shifts it will pinch the voice coil and prevent the cone from moving. To fix this requires freeing the coil and removing the dust cap or whole moving assembly on one of these.

How have you reset the magnet? Not what I’d call a job for a novice.

If necessary, replacement drivers are available new as noted above and also second hand.

 

[DavidRowe]

Thanks, I’m feeling out of my depth and think I’m gonna track down someone to take a look for me.