Ultimation fader - TR6 VN0610L fries

[Artur D'Assumpção]

Hi Paavo,

That would justify the way around, but I have older fader cards with the gel modeld module, and recent ones without it.

Cheers,

Artur

[waltzingbear]

which they probably wanted to get rid of to reduce cost.

a little redesign and you're good to go.

You see the same kind of conformal coating in better condensor mics around the capsule/FET area for the same reasons.  You may not notice it because often it is clear.

Alan

[Artur D'Assumpção]

Alan,

Thanks so much for the info. This is very interesting.

Is this kind of gel molding something one can do on a DIY assemble? Curious how's that achieved.

Cheers,

Artur

[waltzingbear]

Yes, the GC polystyrene coating is good for this. I'm sure there are others, but not as readily available.

here's a general discussion and a DIY version as well!
http://www.cliftonlaboratories.com/coil_coating_compounds.htm#Making_your_own_Q-Dope

that darned internet, it just comes up with the darndest things.  :-)

Alan

[Artur D'Assumpção]

Wow! this is awesome! Thank you very much!

Internet is full of these pearls!

So this coating is something that not only protects physically but also against EM interference?

Cheers,

Artur

[ULH]

Hi
Super happy to hear your experience with servicing Ultimation faders. I have been having the same crawling-issue with some faders in our console and tried to change TR6 with a new BS170 transistor which i found through searching the internet should match the VNL0610 (can't find the link to the database now.). I didn't have success and I am now wondering if this is due to the BS170 type not really matching the VNL0610. I have the data sheet here: http://docs-europe.electrocomponents.com/webdocs/0d27/0900766b80d27015.pdf
I am not experienced enough to compare this to the VNL0610 data sheet. Do you guys mind have a look? And the 1 Ohm resistors that Keith talks about is R74 and R75 referring to schematics T82353.71 right? Cheers and thanks for making sense of the internet-thing ;-)

[kilmister]

At quick look BS170 has pretty same electrical characters.
Pinout is anyway different compared to VB0610L so BS170 have to be turned 180 degrees.

-Paavo

[ULH]

Thanks... That's why.... Feel like an idiot :-)

Another thing: Looking at the same diagram T82353.71 in the lower left corner: The "prestinsert" screw that connects the fader case with the 0V through r26. These screws are very bad on our faders and at best there is periodic contact. Do you think this is an issue regarding common moving fader issues like crawling faders, sticky faders etc.?

[waltzingbear]

No effect on EMI, nada, zilch.

What it does is keep contamination from changing the intercomponent impedances by displacement. Can't contaminate a hole that isn't there. Its now filled with polystyrene.

Or, it cements things down and stabilizes them mechanically as in the references in the DIY article.

In "the old days" this stuff was very commonly used to fix the 15khz flyback transformer in color TV sets that had gotten loose. The kids in the room would be complaining about the squeal and the oldsters would say What?  What noise? Open the set up, discharge everything completely (thats HIGH voltage) and apply the coil dope and let it dry. Mechanical vibrations gone, 15khz buzz gone.

Alan

[Artur D'Assumpção]

Hi Alan,

Always learning! Thank so much for the info you rock \o/\o/

Cheers,

Artur

[xmax]

Thanks! kilmister I have seen that problem many times but was never in the position to fix it. Thanks! N