Help with Sequels

[alharch]

I have a pair of original Sequels and I believe the power supply on one of them has failed. I contacted Martin Logan and they cannot supply a replacement. Has anyone had this problem and how was it resolved?

I replaced the e-panels about five years ago and they sound(ed) really great. Any help will be appreciated.

Thanks,

ALH

 

[Tosh]

I had a PS transformer first go intermittent open and finally fail, but I was able to get another from ML for $16 + shipping. But for months I ran both ESL from the same bias supply....

What's your level of handiness around a PCB and DMM?

 

[alharch]

I had a PS transformer first go intermittent open and finally fail, but I was able to get another from ML for $16 + shipping. But for months I ran both ESL from the same bias supply....

What's your level of handiness around a PCB and DMM?

Very handy and I would not have a problem making repairs.

Could you be more specific about what you replaced? Was it the transformer on the PCB or the large one by the crossover board? Was this before Jim Powers left or after?
How did you rig up to power both ESLs?
Both left and right ESLs worked perfectly one evening and the left one failed on startup up the next evening. I removed the left ESL and connected to the right power supply and it was fine.

Thank you for replying

ALH

 

[MDSPHOTO]

I have a pair of original Sequels and I believe the power supply on one of them has failed. I contacted Martin Logan and they cannot supply a replacement. Has anyone had this problem and how was it resolved?

I replaced the e-panels about five years ago and they sound(ed) really great. Any help will be appreciated.

Thanks,

ALH

Sorry, I don't follow the board as closely as I used to but could have sworn there was thread about ML continuing to provide parts and service for all models when they were sold. Has this changed or do I not have my facts straight?

 

[roberto]

Hola. Write to Dana Brown, he is a very helpful man at Martin Logan service. [email protected] He will guide you to test and find the problem at your Sequels. On the other hand, are you sure about the PC Board? Did you swap power supplies? Do you have electronic skills? Also where the red color hot bias cable, there are five 15Mohms (color brown-green-blue) resistors 1/2 watt. These resistors are connected in series, just follow the foil starting from the red hot bias voltage to the multiplier. I had found open resistors, and that's why the bias voltage is not working. Disconnect the A.C Mains input. Measure the dc resistance at the secondary wound of the transformer located almost the center of the pc board. The secondary is facing the voltage multiplier. That's the transformer that usually is bad. Be careful, because lethal voltage is present there. You need a special probe to test the high voltage. Usually this voltage is around 1800V to 2200V DC. You can check the voltage multiplier also, make voltage comparison with the good one and the other. Happy listening!

 

[Peter Soderberg]

To the ML service question about, the sale of ML has little to do with suppliers being able or not able to supply parts built outside of ML. We will always strive to help, but as speakers get way out there like origonal Sequels, (intro in 1988 if i remember) there may come a time where a repair of a part is the only option. as you can tell with the very experienced Roberto chiming in, repair is an option within the bounds of a good service tech.

 

[Tosh]

Very handy and I would not have a problem making repairs.

Could you be more specific about what you replaced? Was it the transformer on the PCB or the large one by the crossover board? Was this before Jim Powers left or after?
How did you rig up to power both ESLs?
Both left and right ESLs worked perfectly one evening and the left one failed on startup up the next evening. I removed the left ESL and connected to the right power supply and it was fine.

Thank you for replying

ALH

On my SL3 (see schematic), the higher voltage secondary (which supplies the HV ladder w ~260VAC) on T1 on pcb went open, so I connected a clip-on lead to D13 on the still-working speaker and ran a 2-conductor cable over to the failed side.
This was after Jim Powers had left, so I spoke with Dana to get a replacement T1.

 

[roberto]

Great to have a better understanding the circuit design. Thanks Tosh for helping. The resistors at this model are No. 21,22,25 and 26. The xformer is T1 # 60T2706. Happy listening!

 

[Tosh]

Be aware that the Sequel isn't going to look exactly like that schematic, as f.ex. Sequel does not have the music sensor auto turn-on...(?)

There are other things to go wrong in there as well. But don't poke the DMM into the HV ladder or closer to the ESL, unless you are certain the HV has bled off.

 

[alharch]

Wow! Thank you all for such great help.

When my left e-panel stopped working, I removed it and connected it to the right channel power supply. It worked perfectly, ergo it had to be the power supply. Before I posted this message, I called ML and talked with Chris Cosgrove. He asked if I meant a Sequel II and I told him it was an original Sequel not a two. He said he could provide a power supply, but it would take a day or two for manufacturing to re-configure a board. When I received the new board, it was physically different but I could recognize the basic layout of functions. However, I could not reliably determine where the various wires should be attached to the new board. I sent him photos of old and new boards hoping he would enlighten me. Instead he wrote back saying the new board would not work with the original Sequels and gave me an RMA number to return the board for a refund. He said the manufacturer of the old board was out of business. I asked if he could send me a schematic of my board and he said that was against ML policy. He never said what model the new board was intended for but I suspect it was a Sequel II. I can post the pictures of the two boards if that would help anyone. I have not yet returned the new board, but I do plan to do so.

My skills for do it yourself replacement of components on the PCB are competent, but my diagnostic equipment is rudimentary to put it kindly.
I will try to track the cause down further based on the responses I have received already and go from there.

Will post what happens.

Thanks again,

ALH

 

[MPS]

Maybe ML is willing to send service manual/schematics to qualified service center for repairing your original electronics? One possibility is to check what is available in the DIY market, there should be some general HV-boards available with adjustable/selectable output voltage.
DIY audio

 

[Tosh]

Definitely post some pics of all those boards for posterity! All HV supplies are fairly similar. We should be able to at least pin-point your problem.
Curious as to why ML said that board wouldn't work, but if the high voltage output was different from stock that would obviously affect the level. My SL3 pcb has empty places for more rungs on the HV multiplier, so prob inside many ML models.

 

[roberto]

Agreed with Tosh. Pics please!...