SL569 Ultimation PSU weird sounds going to cue busses and afl bus **SOLVED**

[ULH]

Hi

We have a weird sound coming acoustically from the Ultimation motor PSU SL569. It seems like the sound many small sparks(!). The sound corresponds with the fader movement i.e.. the current that the PSU needs to deliver. We cannot see anything wrong inside when the power is on and driving the faders but the big capacitors inside the two 12VDC Coutant power supplies (23000MFD 15VDC) smell like bad fish.

The real issue is that this sound goes to all cue busses and the afl bus meaning that the noise floor goes from around -85 dbfs with the SL569 turned off to about -50 dbfs with the SL569 turned on measured through our Lynx converters into Pro Tools.

Do you know this issue?

Does anybody have the schematics for those Coutant proprietary PSU inside the SL569?

It's a 1994 4064G+.

Thanks guys!

[ULH]

Bump! Any love for info on sl569? 😃


Sent from my iPhone using Tapatalk

[Artur D'Assumpção]

Hi,

The SSL motors is a switched power supply. They  induce noise naturally, although this noise is shifted to a HF range. Sometimes what happens is grounding issues. The motors are very sensitive to it and can induce noise.

How is your current grounding scheme for the SSL motors + SSL logic PSU? Snap some photos. I will compare with mine. I remember that we tested and measured and there was on configuration that yeld less noise (-84db). 

Does this only happen when faders move or as soon as you turn on the motors PSU?

Cheers,

Artur

[ULH]

Thanks for the reply. It clicks a bit when no movement goes on and a lot when the faders move.

The sl569 has earth through the 230v input (the same earth as the rest of the console) and we have tried both with and without the earth linking on the back of it with the same result. Does your sl569 produce any acoustic sound?

I will try to do a recap of it.

Do you think that we could simply buy two new stock 12vdc switch mode supplies if the recap does not work? Or is there some kind of special filtering build into the original ones?

Thanks again 😀


Sent from my iPhone using Tapatalk

[waltzingbear]

if it is a switching supply recapping can be tricky. They are often very picky about the caps in certain parts of the circuit.

It "sounds" like there is a problem with your supply that needs fixing. If it worked fine before and just started happening, then I would suspect the supply. If it has always had a little problem, then I would also suspect grounding in the system. Always ask the question, what has changed in the system? then investigate that.

I haven't looked inside one recently, but many "proprietary" supplies are really just off the shelf oem parts wrapped up in a vendor box. You may be able to cross it to one off the shelf. Often even to the same correct connector.

Open the supply up and see if there are any bulging caps. If it is the large input cap, then that is a pretty plain jane cap that is easily replaced, and often the culprit. Only inspection can tell. You could post a picture here if unsure.

Cheers
Alan

[Artur D'Assumpção]

Hi,

My motors PSU has the ground looped to 0v. That was the configuration that yield less noise when measured with an analyzer (photo in attach).

What seems to happen is that either ground is failing somewhere down the line or it also sounds like a switching/filter problem on the PSU. Maybe a transistor or a capacitor failing?

Do you have an analyzer that you can use to measure the voltage and induced noise at the PSU output?

Out of curiosity what happens if you turn motors off at the computer (MO)? Also if you turn off your motors PSU? Is the noise gone?

Here's a photo:

[ULH]

Hi
Just wanna close this thread. Our solution was recapping and the main change for the better was new output caps in the two Coutant PSU inside the SL569. These caps are 23000 micro farad and we bought NOS from ebay that were totally identical so we didn't risk anything. We also recapped the other main caps with similar but not identical caps. Now it works perfect and I could measure with my oscilloscope that before recapping the ripple were +- 1.5v around the 12v! After it's below +- 0.5v. Still quiet a bit don't you think? But the noise getting to the aux busses is gone so all is dandy now!

I was in contact with Coutant which is now called TDK Lamda before I got the Sl569 fixed. I asked for the old schematics but it was against their customer policy to share it and they of course just wanted to sell me two new PSU's.

Don't buy new stuff - fix the old stuff! 

Cheers,

Uffe

[waltzingbear]

It didn't used to be against their policies, at least of Lambda. They included the schematic with the operation manual.

Alan

[Eric Blomquist]

I'm in the process of recapping, cleaning up and testing my SL569.  Can I turn the SL569 on without the output cables plugged into the back of the unit? Would that mess with the power of the unit?

[ULH]

Hi

Ours made a funny sound when powering on with no load but it didn't mess with anything. I would apply some load for testing purposes if I where you:) It's a switchmode supply of an older design and the switching might not work properly without a minimum external load.

Cheers,
Uffe

[Eric Blomquist]

Thanks Uffe!   Recapping of the SL569 was a success.  My next issue is trying to solve a number of faders that do not respond to Snap On using Ultimation.  All of the faders that have issues when touched individually work if I touch the SSL chassis while touching the Faders.  Where do I need to start to get these faders to work individually without needing to touch the chassis?
Eric

[Matt Sartori]

Thanks Uffe!   Recapping of the SL569 was a success.  My next issue is trying to solve a number of faders that do not respond to Snap On using Ultimation.  All of the faders that have issues when touched individually work if I touch the SSL chassis while touching the Faders.  Where do I need to start to get these faders to work individually without needing to touch the chassis?
Eric

Hi Eric,
if possible I suggest to start a new thread with the problem you are experiencing, this way we'll keep a database of all the problems in a neat and clear way.

Matt Sartori.

[ULH]

Your welcome :-)

Have you done the analogue input test in the ssl computer to see if the computer gets the touch input correctly from that problematic fader? Could very well be the TR6 in the fader that needs to be replaced. Read this thread for further info: http://forum.sslmixed.com/index.php/topic,752.0.html

Cheers,
Uffe