SQ General Stiff Faders

[DaSoundman]

We have an SQ7 which is 4 years old now and all the faders feel stiff to varying degrees. It’s to the point now where if I switch between LR and a Mix some faders don’t quit make it back to the correct position and they don’t move smoothly, they move a bit jumpy. If I switch back and forth multiple times some faders stop a bit further from there correct position each time. It seems like a physical issue to me rather than a software issue. I have tried working the faders physically with the SQ7 turned off in an attempt to loosen them up and that might be helping slightly but not much. Any way to physically lubricate faders to make them less stiff or any other ideas?

[SteffenR]

Don’t use any lubricates. This will kill the motor in the long term.
You can try to clean the faders, but that means a lot of work.

The first I would try is a calibration.

[DaSoundman]

Is there a recommended process for cleaning the faders?

[KeithJ A&H]

@DaSoundman

We do not recommend cleaning the faders with any kind of liquid or spray. Some of these can appear to work, or will work for a short time, but usually leave a residue which can collect ingress to form an abrasive ‘paste’ that will completely ruin your fader tracks.
The SQ faders’ tracks are mounted at 90deg, so they are generally self cleaning and can easily be cleaned by working the fader.
The only other moving parts in the mechanism are the motor itself and the brass spindle at the opposite end with the drive belt running between them.
If you’re having problems with any of these, we’d suggest taking your unit to an authorised service centre as we do not recommend pulling apart the SQ yourself.

Thanks,
Keith.

[SQuser]

I would like to add something from my perspective on this problem.
I have already experienced several SQs with “sticky” faders and so I went looking for the cause.
So I found out that the axis of the pulley of the toothed belt (brass spindle) is resinous on these faders – so the pulley can no longer rotate smoothly and slows down the fader movement.
The result is then, as described here, that the controller deviates further and further from the correct position – but unfortunately also the corresponding parameter.
Unfortunately, the pulley cannot be removed because it is riveted from the back and therefore you cannot clean it and thus make the fader usable again.
The tips given here, such as moving the fader by hand or calibration, do not help in these cases in my experience.
As the problem does not occur more often than average, I assume that it could be a bad batch from the fader manufacturer.

[Sonovero]

I also had this problem with the SQ 5 and can confirm that the grease on the idler pulleys of the belts is resinous.
I was able to remedy this by completely removing the grease and using a little PTFE lubricant on the brass rollers. After that, everything worked like new. This was about half a year ago and everything still runs smoothly.

[SQuser]

Thanks for your confirmation, Sonovero.

> I was able to remedy this by completely removing the grease
May I ask how you were able to do that?
The pulleys are actually not removable because their axles are riveted.
And the axles are thicker on the visible side, so the pulleys cannot be removed for cleaning.
In my case, I was only able to remove the visible resinous grease (see picture).
But despite that, the pulleys obviously did not turn any easier than before.

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[DaSoundman]

I have not done anything yet. I had someone locally recommend a cleaning/lubricating product called DeoxIT D5 and I was ready to try it but chickened out when I couldn’t see a clear way to apply it effectively. It might be a good product for some other application but decided against for this. I especially appreciate the input from Sonovero and SQuser, that makes total sense to me, but I am not inclined to try disassembling the mixer myself. I will be conferring with my partner and see what we want to do, but using an authorized service center here in the U.S. like the moderator has suggested would be my inclination right now. I would forward your comments to them in the process. By the way, we are near Chicago, Illinois, USA. I see the recommended process is to contact an Allen & Heath Distributor to get service which we might do at some point. Keep the replies coming though if anyone has anything to add.

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[Sonovero]

I removed the belt from the idler pulley, just as you can see in the picture from SQuser. Then I cleaned the assembled brass wheel with an assembly cleaner from Würth and a brush. Another assembly cleaner can also be used, it must be able to dissolve oil and resins. It is important to ensure that the belt does not come into contact with the cleaner. The cleaner could possibly make it porous.

[Sonovero]

@ DaSoundaman

I think going through the official service is a safe option. However, I doubt that the service will bother to clean the faders. They will probably install new faders. That is quite expensive and there is a risk that the new faders will be provided with the same lubricant and the problem will reoccur after a few years.
Before I take this step, I would make sure that the new faders are provided with a more suitable lubricant or that the service cleans and lubricates the installed faders.

[Sonovero]

@ SQuser
I used the brush to spread the cleaner generously on the brass roller and kept turning it. Then I gave the cleaner some time to work and repeated the whole process two more times. You need a bit of patience for the cleaner to get into the axle and dissolve everything.

The whole thing would be much easier if you could remove the brass roller. But that’s not possible because it’s riveted in. So only a bit of patience will help when cleaning.

[SQuser]

@DaSoundman
> I had someone locally recommend a cleaning/lubricating product called DeoxIT
It seems to me to be more of a contact spray, which is certainly not recommended here.
The problem at hand is purely mechanical and not electrical.

But: Especially if you have no experience with opening and cleaning such equipment (e.g. never open it when it is connected to the mains!!!), then you should not do it yourself!!
Using a specialist service is definitely the right way to go for you.

@Sonovero
Thank you for your interesting description.
I tried cleaning it with dental floss soaked in alcohol.
Unfortunately, that was not as successful as your version with a penetrating cleaner.
Maybe you could even immerse the pulley in it for a while …

What ultimately helped to solve the problem in my case was rubbing the timing belts a little with a touch of silicone spray.
This made them slide over the pulleys – even if they could not turn or could only turn with difficulty.

If I have a lot of time again, I would examine a blocked fader and drill out the rivet.
Maybe you could even cut a tiny thread into the axle and screw it on.
And maybe we could also find similar pulleys in model making.

Of course we could also buy new faders, but it would be a waste of money and, above all, resources to throw away the old ones just because the manufacturer used the wrong lubricant.

[Author]

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