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roberto

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Hola Wilson,

Can you describe the problem with the CLS? I had an issues long time ago with them. I remember that there was not any DC for the RED color cable (bias voltage). First thing to check are the 15M ohm resistors (Brown, Green and Blue - five resistors) at the end of the ladder DC voltage. Also the transformer. The AC voltage is circa 200V to 260V at the secondary wound of the transformer. Swap the transformers to see if this is the culprit. The bias DC voltage is circa the 2000DCV. Be careful with your tester to check this voltage. You need a high voltage probe to measure this voltage too.

Another thing to check are the solder joints for the blue and black cables at the stat panels. Sometimes these joints are not doing a good contact. You need at least a 100 watts soldering iron to do the soldering.

Happy listening!
 

roberto

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WOW, I just look the pic and that's one of the first CLS power supply. I only see two of these 15M ohms resistors. Anyhow, check the resistors for open.
 

Robert D

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Here is a trick for you, to check the high voltage. ML sent this to me.
Reminds me of when I was a kid and opened up my polaroid camera. I started poking around inside and got the crap zapped out of me! I told my dad later and he said it was probably the capacitor in there. Wow, was that strong! I thought I was safe because I had the batteries out of it.

Getting zapped with the CLS would be just a bit worse,lol.
 

kotedo

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@roberto Do you have any idea on how to "calm" my CLSIIz? When I am in front of the speaker, about 45 cm from the floor, (left speaker), I hear some vibration as if something is "loose". There are also some patches on the foil in this area, they seem to be applied by ML themselves.

These vibrations are the only thing that I am not liking. Any thought on what could cause it?
 

kotedo

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It sounds like a mechanical noise, yes.

I am not snarky, I just want to know:
* What other kind of noises can a CLSIIz panel make besides playing music?
* Can it be the frame?

There is an area that looks like it was dampened by ML ... these panels have never been taken apart.

It seems that the vibrations are coming from that area.

Thoughts?
 

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Brad225

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It sounds like a mechanical noise, yes.

I am not snarky, I just want to know:
* What other kind of noises can a CLSIIz panel make besides playing music?
* Can it be the frame?

There is an area that looks like it was dampened by ML ... these panels have never been taken apart.

It seems that the vibrations are coming from that area.

Thoughts?
As a previous owner of CLSIIz, the dampening tape is a installed at the construction of the panels. It is something they determined was necessary with the evolvement of the speaker.

Have you tried pushing on different places on the frames, panels and interface to see if you can change the issue? Can you look closely to see if the dampening tape is loose? It may just be the photo but it looks discolored. Possibly it is dried out and coming loose.

Let us know what you find.
 
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kotedo

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I just had a long conversation with Roberto, and he listened to it. It seems that the diaphragm is a bit lose, and I am going to (extremely) carefully try to heat up the panel to get it to shrink just enough to get rid of the buzz.

@Brad225 You were talking about "dried out" and discoloration ... wanna tell me a bit more about it? What are the thoughts behind it?
 

Robert D

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I just had a long conversation with Roberto, and he listened to it. It seems that the diaphragm is a bit lose, and I am going to (extremely) carefully try to heat up the panel to get it to shrink just enough to get rid of the buzz.

@Brad225 You were talking about "dried out" and discoloration ... wanna tell me a bit more about it? What are the thoughts behind it?
Do you have an idea now of what might have caused that condition?
 

Brad225

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I think the answer to both is probably the age of the panels and environment they have lived in.

Roberto's suggestion is a good one to try. Other members have used this procedure to tighten the diaphragm membrane successfully.
 

kotedo

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I worked on the left speaker panel last night, only briefly. The outcome is encouraging. I might need to repeat it when I am feeling better.
Nothing beats a Dyson Hairdryer; super airflow and easy to pin point to the critical areas.
 

Leporello

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Worst case you would need to replace the panel. Expensive but well worth it in my opinion. Glad that the hair dryer fix is encouraging though.

If you do end up re-paneling you'll have to decide whether to do just one or both. I did just one, because I had wrecked one of my NOS panels doing something stupid, but if they're both old you may want to do them together. Or just wait and see if the hair dryer trick fixes the other one if it develops problems.
 

kotedo

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... as a side effect ... the concentrated air beam that the hairdryer produces blew quite some dust off the panel, too. :)
 

Leporello

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Here is a trick for you, to check the high voltage. ML sent this to me.
That instruction seems to assume your multimeter is a particular impedance (ohms/volt). But if you have another speaker to do "comparison shopping", the precise voltage measurement shouldn't be critical, as long as you have one good speaker and it's the same.

You could try shopping on eBay for high voltage probes. Since not many people are repairing CRT's any more, there should be a surplus of them. I got a Fluke for $14.
 
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