Martin Logan Aerius --no sound from ESL section

stalljs

Member
2016-04-19 5:40 pm
Hi. First post. I purchased a pair of martin logan aerius speakers which were sold as having outstanding sound. After paying over 550. for safe,fast shipment. I received a pair of huge boxes for each packaged by ups store and delivered in 2 days . The boxes contained no padding other than 1 layer of bubble wrap but tons of room to bounce around in transit. The seller said that the no sound situation from 1 was probably loose or broken wire. I switched panels, transformers, and then finally the circuit boards where the problem was discovered. One works, one doesn't but both show signs of contact heat blistering under an as of yet identified component which is purpose of my rant and post. Could someone please identify component on circuit board with zip tie around it.and where might it be purchased.. Pic enclosed
 

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stalljs

Member
2016-04-19 5:40 pm
Thanks for quick reply.. ..I looked at suggested thread and if I were more knowledgeable I would be able to make sense what was written but since I'm not but do own a good multimeter would you know where on this component to take such measurements. I'm guessing on the underside of panel. Would you know? Thank you
 
What brand/model multimeter do you own?
You can make measurements from the component side of the board...I will post an image showing test points when I get home tonight. The transformer is the most likely part to fail, but there have been other components go bad.

A first step before measuring anything is to make sure the signal is getting to the triac switch to send voltage from the transformer to the voltage multiplier stage. Does the red LED on the board light up when power is plugged in? You may need to feed an audio signal to the speaker binding posts for it to illuminate.

Circuit posted for reference.
 

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stalljs

Member
2016-04-19 5:40 pm
Hi. I'm not where meter is but it is fluke 175 I think. Light stays on when audio signal is detected. i swapped out panels, then transformers,finally circuit boards. Only when circuit boards were swapped was the problem found. somewhere in 1 of the boards. Although, when viewed underneath there is heat bubbling at solder points under each of the zip tied components on each board. But one works, and the other board does not.
 
Hi. I'm not where meter is but it is fluke 175 I think. Light stays on when audio signal is detected. i swapped out panels, then transformers,finally circuit boards. Only when circuit boards were swapped was the problem found. somewhere in 1 of the boards. Although, when viewed underneath there is heat bubbling at solder points under each of the zip tied components on each board. But one works, and the other board does not.

Fluke 175 is a great meter. :up:
Light coming on with audio signal lets you know that transformer is receiving voltage from the mains supply and the low voltage winding is working properly.

Next, check the output of the transformer High Voltage winding.
The attached image shows an easy place to put your meter probes to measure.
Voltage should be around 240VAC - 260VAC if the transformer winding and Zener regulation is working correctly. A very low or zero reading lets you know either the transformer HV winding or connection from the winding to the PC board traces has failed.
 

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tyu

Member
2009-07-18 8:16 pm
I have Been buying used ML for years now.......one place I have over looket...is the bias feeder res......there 15meg......I just got a pr that had low-to know output panel.....
I now have a outboard bias......so all I do now is open up the bass box... pull the red panel bias wire out an the center tap of the setup tran.....put in my bias to ck the panel

real time saver...last pr what I found...the last res in the bias feeder res....was open!
that's right.... that one 15meg res right at the red wire output off the board...had went open..an stop the panels output.....thats where I would start......
But as bolserst is showing you... the bias tran... has to have output....
but I well say....out of 15 pr of the ML....that's 30 bias boards....none of the bias tran were out......all just one mans finding...............good luck
 

stalljs

Member
2016-04-19 5:40 pm
Hi. I just checked voltage between 2 points on the working speaker and had a 250v reading. Meter between points on non working one and 3 or 4v showing. Is that it? Or should i test something else while in this area. And if the answer is check something else, please use picture of board as was done before. And if no more checking is answer, do you know where best place to purchase this transformer? Also, is it normal for solder points on underside of board where this part connects to show blistering? Thank you
 
You have isolated the problem, nothing further to test.
Voltage is going into the transformer, but not coming out.
Can you post picture of the blistering you are talking about? I have not seen that before.


Andersonix had an open secondary on one of the HV transformers for his SL3s.
He was able to get a replacement directly from Martin Logan for $16 + shipping.
I believe the transformer part number is the same as yours.
http://www.diyaudio.com/forums/plan...ittent-bias-supply-problem-2.html#post3085792
 
Hi guys,

Motivated by the info in this thread, I picked up an Aerius pair today that was supposed to be defect.
Yet, they are now playing in my room, and nicely so.

There IS a problem though, one of the woofers has a rattle. Switched speakers so sure it´s the speaker.

Does anyone have a schematic of the xover? I have a copy of the HV bias and auto switch on schematic, thanks for that, but not the xover.
Also, any info on that woofer type and or brand would also be welcome.

Jan