Sudden restart of module

so i tried to replicate this reboot problem with extensive walking around an all carpet studio and rubbing myself awkwardly against stuff…but it didn’t happen today. so, again i’m lost, power issue it is not, static electricity test failed…what else could it be? i didn’t had a patch running today…so maybe it’s also related to cpu usage? well anyway, happy that nothing happened today but also not happy since no answer to the problem in sight.

Did you get a noticeable static discharge? I am able to reliably build up a little static charge by moving from my computer to my modular setup (e.g., to reinsert the SD card to load a new firmware), and my ER-301 would restart without fail if there was a noticeable spark. After grounding the encoder housing as @odevices has described, I can zap the encoder knob to my heart’s content without so much as a hiccup from the ER-301. It has completely solved the issue for me.

Given all of the potential variables, how does one achieve such a state of certainty? :dizzy_face:

faith, pure faith…but no i tested my power supply when i built it (well not me, a professional). i have an external doepfer psu3 and since i switched to that all my power problems went away, so that’s why i believe in it…aaand of course because this reboot problem only happened in this new carpet studio…so i still think it’s static electricity.

In about 5 hours of usage last night my ER-301 rebooted twice, and I believe both times it was when touching the encoder after a few minutes of not touching it.

I do frequently get static shocks in the winter, though I always discharge myself on furniture before touching my synths or computer. With my current case situation, my ER-301 is mounted in a spot that encourages standing up to reach it easily, so I probably built up just enough charge doing that to zap it a couple of times. (I have a new case which should be shipping soon and the ER-301 will be placed much more conveniently.)

I’ll take more care about static, and also look into grounding the encoder housing. And also try to get into the habit of quicksaving :laughing:

Known issue, for some folk, I have never experienced this, but me and electricity are very best friends and we allow each other a great deal of leniency; answer here…

The encoder on your unit should already be grounded. What is your case ground attached to?

I’m using a TipTop Mantis for now. Its PSU is plugged into a power strip. Unfortunately I’m in a room where only one outlet is grounded, but I have the power strip plugged into that one.

I have a 14GA wire with a spade lug under a screw on the front panel of the Mantis, going to the front panel of my other rack (because I was having noise issues with my Doepfer A-180-9 Multicore until I did that). But that’s the bottom row and my ER-301 is on the top row.

I ordered a new case from MDLRCASE a few weeks ago, so all of this is going to change (soon I hope).

Having said that… electricity may kill me one day!


I mean, is the info I linked to no longer relevant because of an update in the way the modules are built now?

No it’s fine to link to that thread. Although I have started grounding the encoder housing since then, it is not a 100% verified solution because I’ve never been able to replicate the original problem here in my workshop.

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I had frequent and repeatable restarts (especially during dry winter months) before I grounded my encoder, and haven’t had one since. I simply taped a small length of wire between the housing and a ground pad, so that’s something easy to try.

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So after some more detective work, I’ve discovered that it is possible that the knob grounding that I introduced in recent units might not be doing the job in some situations. Essentially there are 4 exposed ground pads underneath the (metal) encoder housing that are meant to be in contact with the encoder and hence ground it. However it looks like in some cases, tightening the nut on the encoder bushing will ever so slightly lift the encoder housing away from those grounding pads thus breaking the connection. :cry:

Luckily there is a pretty easy fix if you have some needle-nose pliers that takes about 10 seconds and you don’t even have to remove the panel.

How to ground the knob

There are 4 pins extending up from the board to the left of the encoder. Take the pin that is closes to the main display (i.e. the upper pin) and bend it 90-degrees forcing the tip of the pin into the encoder housing. It is important that the tip of the pin is securely pressing into the encoder and not the side of the pin.

The easiest way that I have found is to grab the tip of the pin with the tip of your needle-nose pliers and slowly twist the pliers so that the pin bends towards the encoder housing:

Of course make double sure that you are bending the correct pin! You should be bending the pin that is closest to the main display.

Finally, for extra credit, take a voltmeter and measure the resistance between the GND test point on the back of the module and the encoder housing. It should be less than 0.5ohms.


I’m glad you mentioned this part – I thought I had the pin bent over enough, but it was just a fraction of a hair’s width too short and didn’t actually make contact until I gave it another few tries.

I’ve only rebooted the module three times in the first week of heavy use, so I won’t really know for sure that this fixes it until… I guess if a few weeks pass without trouble. :slight_smile:

Thanks for giving it a try :bowing_man:
Let me know how it goes.

Wouldn’t a blob of solder give the final touch?

that is a reasonable question to ask…
we discussed that question in post 9

Please do not solder the encoder housing :wink:

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Oops, sorry I missed that…

Wow this is good news… I just rebooted my 301 twice in a row by touching the encoder. My house is dry right now and i can generate static like some marvel super hero. Ill look into bending the gnd pin in.

A little nervous to modify my most expensive module but ive done some wire bending and ive built modules before so i have some experience.

Wish me luck

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I’m surprised I’ve never tripped mine as the humidity of my studio is relatively low!static_hair_kid