Needing help with Ascent's

[Capt.Willard]

Hi All!
I have come into possession of a nice pair of ML Ascent loudspeakers and they have a few issues to get sorted out.
One side has Zero output at all just a constant red led that indicates electrical trouble.
The other side plays but I have no red light ever.
I have opened it up and looked inside.
Everything looks in order, no wires shorting at the woofer and no fuse to be found anywhere on the circuit board or elsewhere.
Obviously it has power to the board and LED indicator on the front of the speaker works...any ideas other than contact ML?
Thanks!

 

[Tosh]

So one works totally fine? Swap the PS board L to R, so as to isolate the problem to the PS board.
Look at SL3 HV PS diagram attached and check if you're getting output from T1.

 

[Capt.Willard]

So one works totally fine? Swap the PS board L to R, so as to isolate the problem to the PS board.
Look at SL3 HV PS diagram attached and check if you're getting output from T1.

Thank You for the response!
I will check it out and report back.

 

[Capt.Willard]

Schedule conflicts have been keeping me from looking at this again until last night.
Disconnected the wires to the snap connectors on the board to remove it to have a closer look.
Wasn't able to remove board as I didn't have the required square driver bit so reattached the wires and now I have bass section/frequencies functioning where before I had nothing but a dead speaker so hurray for just poking around.
Both LEDs illuminated very briefly then extinguished.
Perhaps it was in some kind of protect mode before when both leds were on constantly?
This speaker's panel shows no sign of having slipped down.
So where/what to check now?

 

[Tosh]

The bass is an independent circuit and doesn't go to the board, so you must have poked something else. Lots of 20 year-old connectors in there to freshen up.

The attached SL3 diagram is basically the same circuit that Ascent uses, but the Ascent board is more compact and uses different part ID numbers from the SL3. If you have one working board and one not, then you can compare them.

 

[Capt.Willard]

I appreciate the help.
I'm going to see if I have voltage to the esl panel at the quick connectors and go from there.
It's easier to have a look there first without opening the back up again but I suspect I will be there checking output at t1 as the next step depending what I find.
If it shows voltage there that will let me know if the panel connectors may have broken contact even though it looks like the panel hasn't dropped without me having to drop the panel to get eyes on the connections to confirm.
I have a high voltage probe.
I guess I'm looking for about 3k volts thereabouts at the panel quick connectors?

 

[Capt.Willard]

OK going thru these I determined the transformer on the high voltage board was bad but ML wouldn't sell me the part so I had to bite the bullet and buy a new board. Installed it and we have our loudspeakers function back.
Sounds great!

 

[Tosh]

How much for the whole board?
10 years ago I had a bad T1 on my SL3, and ML sold me a new one for under $20, and that transformer looks the same as on my Ascenti....

 

[Capt.Willard]

How much for the whole board?
10 years ago I had a bad T1 on my SL3, and ML sold me a new one for under $20, and that transformer looks the same as on my Ascenti....

$370.00 ouch!
But they work now.
I am now contemplating washing the panel/s.

 

[Tosh]

Yeah, that hurts!
Showering is a last resort before ordering new panel$$$. If you're having other problems you should look into that first. It could be that a panel like yours that hasn't been charged up for a while needs a whole day (hours) to charge fully (and the music sensor keeps switching them off!), so wait to decide.
Now that I have clear spar Gen2 panels I don't worry about needing to shower them, but back with the old SL3 I wondered how to best accomplish a soak for those porous foam spars. But fortunately I kept after them with a magnifier and brush, so they stayed clean.

 

[Capt.Willard]

I certainly appreciate the tips!
I have many of the same concerns regarding the foam spars.

 

[Tosh]

On the one hand those 3M adhesives were pretty good, but on the other hand those 3M adhesives are 2 decades shrunken up, dog knows what will happen if they get wet!
I imagined a bathtub full of special water and an ultrasonic wand to agitate...

 

[Tosh]

Don't lose track of that non-working board, as it may be repairable!
If you have the opportunity, I wouldn't mind seeing a close-up photo of it.

 

[Leporello]

Normally, red light indicates bias voltage is on.