My 301 is dead! Need help please

My Er-301 deos not start up. It was working perfectly and suddenly stopped doing anything.
What can I do? I need help.

My best.

Need a lot more info. Did you add anything recently? Have you taken anything out? Changed your power supply? Checked your connections? Any other modules showing any symptoms?

Do you see any lights coming from the 301? Specifically the green one that is used with the encoder?


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Were you using the 5V or 12V power setting on the dip switch? If you were using 5V and plugged the power cable in backwards it will fry the processor (learned this the hard way :sob:)

I have a stupid power brick with 12v / 15v / etc… settings and it sometimes switches to 12v instead of 15v (it probably get’s knocked) and this causes things to not light up - it’s horrible - it’s my least favourite thing about my modular.

Check SD card is properly inserted?

…and yes - everything @2disbetter said!

I had it in a MDLR case with Doepfer psu3 working perfectly, no inverted power, its imposible because the bus board just got one position. I changed it to a new mdlr case with the new power from mdlr case and it Didnt power up.
It deos not power up ante here anymore. Everything else is working perfectly in the dame case, just the ER-301 dud not power up

No ligths


Obvious question: What are the power limitations of the new case vs. the total amount of power draw from all the modules?

The power is correct, the same as the psu3. That shouldn’t be the problem. It’s very very strange.

Okay, but I can’t really deal with ‘shouldn’t be’ - to debug things I need to look at specific measurements and confirmation by double checking things.

Seriously, add up the total power draw of all your modules and make sure it isn’t exceeding the maximum power available - typically ~80% of the rating. A quick way to do this is on modular grid.


I plugged it back where it was working for month and nothing.seems to be totally dead.

+12V / 2A

-12V / 1.2A

+5V / 1.5A

Output stability ±1% for 0-100% load

Input 18V ( 16V – 20V )

Output Connectors 40 x 16 pin IDC for flat cable

Input connectors WAGO spring terminals + 5.5 / 2.1 DC inlet

This is for 2 rows of 104hp. There is more than enough to power😐

Cool - that’s good info - nice power!!!

You’re probably right, but there are some very power hungry modules out there and I would wager its totally possible to exceed even those (admittedly ‘very’) generous specs, I would check it, but that’s me, up to you :slight_smile:

Next obvious question is are all your connectors the correct orientation, again, personally I would go through each one again, regardless of how many times I had checked and double checked.

The next thing is to try powering up the ER-301 on it’s own.

Then take the SD card out and make sure it’s working correctly on your computer.

Oh and also check the SOM module on the back of the ER-301 is on properly.

Just got this red light at the back

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Kel, everything is plugged perfect it’s not working anymore in any of my cases. All other modules work perfect in the same row, I can see at the back of er-301 there is a rst button. Could I reset it? Should I chek the SD on the back of the 301 in my laptop?

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Yeah definitely - see the troubleshooting section on the Wiki:

Oh sorry - I can’t remember what the reset button actually does!

Thanks kel. I will keep trying but this is a weird one

don’t worry mate, I think most of us have been there before with equipment. at least we know we are in good hands here…:slight_smile:

I do not know what to say, everything is connected properly and suddenly I can see some smoke on the olimex board. It gets pretty hot.

What happened? No reverse power connection.
It’s on the bUS 5V position.


Have you got a multimeter? If so can I suggest checking the power on the rails.

Can u see the burned one