ML SL3 power problem in one speaker

Hi, I am new to the forum and a new owner of a used pair of SL3s in excellent condition and with excellent sound quality. But after I brought them home (handled gently and with a trip of just a few miles) and I hooked them up, one of the speakers had a problem: both speakers would work beautifully for a few minutes and then one would start to develop crackles and then stop making any sounds at all. I switched out power and speaker audio cables but the problem remained in the one speaker. Other times after powering off and restarting, the problem speaker would be silent from the start. I have no electronics background, but what else can I do? I blew my limited budget on these amazing speakers and can't afford to bring them straight into the shop! Thank you very much for any advice.

Best bet is to contact Martin Logan. Sounds like it may be a power supply issue. They can help you troubleshoot and if it is a power supply problem they can send a fix or replacement to you. I had a power supply go out on one of my ML speakers and they didn't even charge me for a replacement power supply. Good luck.

Hola. It looks like a solder joint failure at the panel. You can re-solder the joint, with a 100Watts soldering iron. If you do not have soldering skills, it would be wise to find someone who does. Follow our friend´s SlowGEEZR advise, and call Martin Logan service dpt. They will guide you to how to track your problem easily.

Thank you very much, I'll contact ML today. In the meantime, if the LED lights are glowing in each speaker, does that mean the power is working fine in both?

rbullock said:

Thank you very much, I'll contact ML today. In the meantime, if the LED lights are glowing in each speaker, does that mean the power is working fine in both?

Click to expand...

No, because there is a separate winding on the transformer (see attached, T1) to the HV ladder that could be broken. Another winding supplies the music sensor and the LED.

BUT, if it's "crackling" then you most likely have a break in one of the three soldered connections to the panel (or audio step-up transformer -- not so likely), and you prob don't have a PS problem.

If ML hasn't helped you out yet, start with a sensible approach to troubleshoot the problem.
Easiest first step would be to swap the rear panel between speakers to see if the problem remains on the same channel.

You said the speaker played fine and starred causing problems after a few minutes, does it work fine again after you let it sit for a few hours? That would point to a heat, thermal expansion, problem. A can of freeze spray might help narrow things down if that's the case.