Those speakers are excellent and worth a thorough rehab! Everything on them can be replaced if it's broken. Many of us audio geeks replace capacitors in the crossover and (depending on condition) the woofer foam surround as a matter of course.
Great advice above from all contributors I think. I'd follow these steps to isolate the problem component:
- Take a pic of the speaker fully assembled so you'll know any details when you go to put it back together.
- To dig the tweeter out of its mount, put the speaker on its back and carefully use a skinny pick or hook and a plastic tool like a putty knife to pry it loose. Be gentle but persistent. It will eventually come out and you are unlikely to do any damage.
- Note the two connections on the tweeter and the wire color that goes to each - a pic is worth 1000 words.
- If you're happy with the other speaker or it is at least working, switch the tweeters and see if the problem follows the tweeter or the cabinet. If the problem follows the tweeter, you need to replace it.
- I don't have that model but most speakers use the woofer hole for access into the cabinet for electronic repair. So remove the woofer the same way as the tweeter. It's much heavier (~5 lbs) so you may need to tip the speaker upright and be ready to catch it as it comes loose. Again, take a photo of the wire before disconnecting.
- Scratchy sounds suggest there is probably a loose or corroded connection. A loose wire is easiest to diagnose and fix. Just look for any wire connections inside and wiggle everything to see if you get the sound.
- The Lpad is the dial thing as stated above, typically a component called a potentiometer, and will have marks that specify its value in ohms, typically 25 or so. A corroded or worn Lpad is a highly likely candidate as other posters stated. To see if it's causing the issue, bypass the Lpad with a jumper wire (connect the tweeter directly to the wire on the Lpad that is not already connected to the tweeter. Alligator clip test leads are great for this but any wire will work.
- If the Lpad is ok, the next thing to check is capacitors. They are usually cylindrical components marked by a number to specify their value followed by the abbreviation "UF". The "U" is the Greek letter mu (short for "micro", or 1 millionth) followed by F which is "farads", the unit of capacitance. A capacitor marked 10 UF 100V is 10 microfarads and good up to 100 volts. They cannot be tested in place, and (unless you get crazy audiophile brands) they are cheap, so consider replacing them. Dayton is the brand I use because they're easy to get.
- If either the Lpad or capacitors are causing the problem, you will likely have to desolder them and solder in the replacement parts. It's not too tough but you might want to watch a video or phone a friend. But before doing anything, get a picture that clearly shows every wire, component, and connection.
Given this is your first repair, I'd suggest replacing any components with similar electronics. While some feel they are not audiophile quality, I personally have had great results with new reasonably priced electronics from Parts Express and many other vendors. To each his/her own approach.
If all else fails, used working original drivers will be on eBay at some point, and tweeters usually aren't too expensive.
If you catch the disease, your next purchase should be a digital multimeter. Good luck!
