Found Solution to the EMX-1 and ESX-1 Knob Jitter-Issue

DrNibbert · Post by **DrNibbert** » Sun Feb 26, 2012 11:10 pm

Hey everybody!
if you landed here, you are most likely experiencing the same isse that i hat - until finally i found the solution today!

(If you don't know what I'm talking about, you can find an example-video of the problem here: http://www.youtube.com/watch?v=HPzEjCyEgeU )

I allways assumed, that the problem must be mechanical, because it got worse when i was pushing the front plate against the housing.

Searching the Internet, i found suggestions to use contact spray - but i was shure this couldn't be the problem, because, as i said, the problem also occoured only from touching the front plate.

So, long Story short:

The Problem is, that the upper circuit Board is mountet very close to the lower one, so when you put force on it, they touch, create a chort-circuit and make the controller go crazy.
www.nhx-music.de/stuff/emx-1/1.jpg

To Fix this, you first need to take of the blue or red frontplate by pulling of the plastic knobs and loosening the hexagonal bolts.
Secound, unscrew the 4 grey screws on the plate below (see Image).
You don't need to unscrew the black screws.
www.nhx-music.de/stuff/emx-1/2.jpg

You now can take of the top part of the unit.

My solution to fixing the problem, was to put something in between the circuit boards, to prevent them from touching.
Considering that the EMX uses tubes, and tubes tend to get hot, i wouldn't use any flammable material like normal paper. I used baking paper, but a better solution would be thin plastic foil or something similar.
So i just had to cut out a piece in the size of the circuit board, tape it onto it. And i was done!

www.nhx-music.de/stuff/emx-1/3.jpg
www.nhx-music.de/stuff/emx-1/4.jpg

I tested it the whole day, i didn't experience a single knob jitter!

neotechtonics · Post by **neotechtonics** » Mon Feb 27, 2012 10:59 am

thanks for this post. I've had a problem with knob jitter on my EMX-1 SM. I'll have a look at trying this fix once I get it back up and running (needs a new power adaptor) This is something i can try before going the route of replacing/servicing potentiometers. hope it fixes the problems.. i'm tired of parameters shooting off at random when i play on the arpeggio ribbon.

thehighesttree · Post by **thehighesttree** » Mon Feb 27, 2012 10:52 pm

KICKASS POST DOC!

...but before I get too excited, I'm curious to know you diagnosed the shorting? Hopefully this puts all the jitter issues to RIP.

Marsu · Post by **Marsu** » Tue Feb 28, 2012 8:09 pm

thank god there is a solution! I need to do this asap. Is that blue tape some special kind for electrical work or would anything go?

DrNibbert · Post by **DrNibbert** » Wed Feb 29, 2012 4:23 pm

Thanks for your reply!

I found this solution "by accident" when i opend the unit while it was still powered on. I took of the top part (as shown in the pictures) and placed it on the metal enclosure, so the enclosure touched the bottom-side of the circuit board, when suddenly the parameters began to change randomly like they do when "knob jitter" occurs. I tested it with other conductive materials (randomly touching the bottom side of the circuit board) and got similar results, so i figured that must me the reason for this to happen.

I used simple Insulation tape, but it has no specific function so any kind of tape will do, as long as its a electrically non-conducting material.

I hope i didn't promise to much, but as far as i can tell from my emx the problem didn't show since then!

thehighesttree · Post by **thehighesttree** » Wed Feb 29, 2012 5:53 pm

It makes a lot of sense and sounds like you isolated the problem. Any recommendations about an insulating material to use?

Eat-Static · Post by **Eat-Static** » Wed Feb 29, 2012 5:59 pm

DrNibbert wrote:I found this solution "by accident" when i opend the unit while it was still powered on.

DrNibbert wrote:(randomly touching the bottom side of the circuit board)

Don't let Health & Safety hear this

Let's hope noone is silly enough to get ELECTROCUTED

Eat Static (No dont eat it)

DrNibbert · Post by **DrNibbert** » Wed Feb 29, 2012 8:13 pm

Let's hope noone is silly enough to get ELECTROCUTED

You're right, it can be extremely dangerous to open a device if it's still pluged in. On the other Hand: The power supply outputs 9V, so it's not more dangerous then touching a 9V-batterie. BUT of course creating random shortings can damage the unit, so "Don't try this at home!"

Pastor-of-Muppets · Post by **Pastor-of-Muppets** » Thu Mar 01, 2012 1:13 am

DrNibbert wrote:The power supply outputs 9V, so it's not more dangerous then touching a 9V-batterie.

Yeah, if you ignore the fact the ESX transformer puts out far more current than a 9v battery and that AC is more dangerous than DC. But apart from the ways it's more dangerous, it's no more dangerous.

los vlados · Post by **los vlados** » Fri Mar 02, 2012 5:35 pm

Thank you very much for the experiment - solution. I have this problem on my ESX since 2 years, really thank you.

Bowmoney · Post by **Bowmoney** » Fri Mar 02, 2012 6:53 pm

Pastor-of-Muppets wrote:
DrNibbert wrote:The power supply outputs 9V, so it's not more dangerous then touching a 9V-batterie.
Yeah, if you ignore the fact the ESX transformer puts out far more current than a 9v battery and that AC is more dangerous than DC. But apart from the ways it's more dangerous, it's no more dangerous.

yeah, volts don't kill you...it's the amps that kill you

Pastor-of-Muppets · Post by **Pastor-of-Muppets** » Sat Mar 03, 2012 1:34 am

Bowmoney wrote:yeah, volts don't kill you...it's the amps that kill you

exactly. I've had THOUSANDS of volts go through me, it's really fun to make your hair stand up with a van der graaff generator - but the current (i.e. number of amps) is really, really tiny, so it's safe

a groovebox plugged into the mains IS NOT SAFE

whiteleech · Post by **whiteleech** » Sat Mar 03, 2012 8:37 pm

holy crap!!!

DrNibbert, i actually love you, like literally, actually love you!

this problem has plagued me for like 2 years up to the point where it was almost impossible to use, i had to save it after change otherwise it would spin out of control, completely ruin all the settings and i'd have no idea what it had changed

saw someone mention that you can take it apart and use cleaning lubricant so i ordered some, took my emx apart and thought... i'll just check online once more... and came across this thread!

cut out the baking paper and placed it in between like you said. didnt use tape as i didn't have any heat resistant tape. screwed it all back on and haven't had one issue yet!

thank you so much!

thehighesttree · Post by **thehighesttree** » Sat Mar 03, 2012 11:34 pm

All the old guys here seem to be super-jealous of Nib's surgical techniques.

But really though, enough talk about how potentially dead Dr.Nib could be, we've finally got a solution to this issue! It's the only major quality concern I've heard about these boxes, and to have that rectified is huge.

keyboard chris · Post by **keyboard chris** » Mon Mar 05, 2012 7:11 am

How do i Remove the knobs ?

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Found Solution to the EMX-1 and ESX-1 Knob Jitter-Issue

Found Solution to the EMX-1 and ESX-1 Knob Jitter-Issue

removing the knobs