I had a similar issue with my 3 yr old X-540 speakers..power surge caused a blown fuse and the sub just wouldn't power on....there was very little info on google..and Logitech doesn't make these anymore so no help from there either...finally took it to a local speaker guy..who happens to be a friend of a friend...and he affixed it with a new transformer and coil...paid 800/- ..speakers working like new now
During my recent expedition to fix a speaker I found a few audio repair shops near Ritchie street. Most of the audio repair shops are in and around the streets behind the P. Orr & Sons showroom, take the left turn just before the P. Orr & Sons showroom and if you take the first right there are a few speaker repair shops in that lane. In a neaby lane called Seeyaliamman koil street there are a few other shops which repair speakers