Thursday, August 30, 2012

Buzz off

Ever since I received the Elecraft KX3 it has suffered from poor loudspeaker audio. It buzzed and distorted at any but the lowest volume level. Various suggestions were made and considered but the culprit seemed to be the loudspeaker itself. Elecraft spotted my description of the problem on the KX3 Yahoo group and offered to send a new speaker. After confirming to my satisfaction that the speaker was indeed the culprit I accepted the offer. The replacement came in the post this morning.

The culprit(s) revealed

It didn't take long to plug the new speaker into the KX3. To my dismay, that buzzed and distorted too. It didn't seem to be quite as bad as the original, though, so I decided to install it. That was when I hit a snag: the holes in the speaker chassis had not been tapped to take the mounting screws. I was stymied.

Thinking I would have to put the old speaker back, I had a good look at it. That's when I noticed a split ring lock washer stuck to the magnet where it joined the speaker cone. Aha! I thought. The culprit! As I was soldering the speaker leads back on I noticed something else that should not have been there. A second lock washer! I fished it out with the end of a jeweller's screwdriver and put it with the other one.

I hoped that would be the solution and prepared to reinstall the original speaker. While I was thinking about that I was examining the replacement I had been sent and I noticed what looked like the edge of another split ring lock washer. After a bit of fiddling with the jeweller's screwdriver I managed to fish it out. Yes. it was a split ring lock washer, stuck to the magnet of the replacement speaker!

I'm sure some of you are thinking that my shack must be a tip with bits of hardware strewn all over the place, but I assure you that isn't. I can easily see how a small part could get dropped inside the KX3 during assembly and migrate to the speaker's powerful magnet. But how one came to be stuck to the inside of the replacement in a sealed envelope straight from Elecraft will probably forever be a mystery.

I'm happy to report that the audio from the KX3 is now perfect at any reasonable volume, with the original speaker reinstalled in it. If any UK KX3 owner needs a replacement speaker then it's yours for the asking. But you'll have to tap threads for the mounting screws into it.
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