ML ESL Trouble

[NLaudiophile]

So it’s been awhile since I posted in here! But like before I’m in need of advice. I purchased my ESLs in 2013. Had them set up for about 4 years, no issues.
We move in 2018 and I pack up my speakers in the original packaging. They were stored in a spare room until last week when I finally had my new theatre room ready.
I purchased a new Anthem MRX 740 figuring that it would be strong enough to power up my ESLs and FX2s for surrounds and rears.
I set it up, turn on the receiver, seconds into it, it shuts off showing “Amp protect”
I turn it on again but decide to run the ARC genesis. It started with the Front Left ESL. The tone sounded for about 2 seconds, then I hear crackling, then static for about 3 seconds, and I get a message, critical sound issue. Sound stops in the speaker.
I then smell burning and see a little smoke from my speaker…

What happened to it? Is this a common issue? Can it be a receiver issue?

Any help is greatly appreciated.

 

[ttocs]

Smoke is never normal.
You're going to need to open up and look for what is burning.

 

[NLaudiophile]

Smoke is never normal.
You're going to need to open up and look for what is burning.

I took the bottom off, but didn’t disconnect anything so it was hard seeing everything inside. Having said that, I couldn’t see anything burned but could easily smell it.

 

[JonFo]

This is why I keep a Variac around, as it allows one to gently power up gear that has been offline for a long time. A must for really old stuff, but still helpful on many modern designs.

What happens is the caps get fully drained after a year or so and when you just plug it int to the wall and hit it with 15A of 120V, sometimes those caps can't take it and go 'poof'.
But if you ramp it up via a Variac from 20v slowly up to 110v (going slower the higher you go), the caps can charge slowly and come up to spec.

So my guess is the power supplies in the ESL are what fried and will likely need repair or replacement.

 

[NLaudiophile]

This is why I keep a Variac around, as it allows one to gently power up gear that has been offline for a long time. A must for really old stuff, but still helpful on many modern designs.

What happens is the caps get fully drained after a year or so and when you just plug it int to the wall and hit it with 15A of 120V, sometimes those caps can't take it and go 'poof'.
But if you ramp it up via a Variac from 20v slowly up to 110v (going slower the higher you go), the caps can charge slowly and come up to spec.

So my guess is the power supplies in the ESL are what fried and will likely need repair or replacement.

That makes sense.

So I decided to hook up another receiver to my system as a test. It’s new but much less power. Everything worked fine, which suggests the Anthem is definitely faulty.
But my speaker is still gone. Having said that, I could clearly hear sound from the panel, but nothing from the woofer. Does that make sense, and what needs to be repaired?

 

[JonFo]

I think the second receiver worked because by then, the circuits on the ESL were toast.
It is possible the Anthem was fine, but when presented with a really weird load (possibly with back-currents) the system failed with devices fried on both ends.

You will definitely need to repair the Anthem.

Did the ESL work fine (panel & woofer) with the second receiver?

 

[NLaudiophile]

I think the second receiver worked because by then, the circuits on the ESL were toast.
It is possible the Anthem was fine, but when presented with a really weird load (possibly with back-currents) the system failed with devices fried on both ends.

You will definitely need to repair the Anthem.

Did the ESL work fine (panel & woofer) with the second receiver?

No, just the panel with the second receiver, no sound from the woofer.

With the first receiver, nothing from the speaker worked and the receiver shut down again. That’s completely disconnected and ready to be returned!

 

[JonFo]

OK, then the woofer amp or power supply is toast and will need repair/replacement.

The lesson for those reading along: when reconnecting old gear such as powered speakers, amps, or anything with large caps that have sat disconnected from AC for extended periods, especially years, use a Variac to gradually bring them back online, and do not connect them to anything until it has run and settled for 30+ minutes. If the unit becomes unduly warm, then suspect something might be amiss.