Rambo 1.4 board failure - early life failure :(

I have recently completed the build of my first MPCNC (an all together fantastic experience - recommended to all!), and having been very happy that I had got the thing running (Printed Crown GCODE without a hitch), Dual endstops working correctly, etc. I was attempting to get into a bed leveling exercise when all of a sudden my board made a “Pop” sound, the speaker let out a warble (first time I had heard it make any sound), and the display screen lost all sync.
I pulled the power at this point.

This is a V1 supplied Rambo 1.4 board - bought 12 April (arrived some weeks later), so not used for more than about 3 hours in total so far).

Only possible hint of any issue I had found was that homing on X or Y seemed to time out if distance to travel home was too far (other side of bed, don’t know if there is a limit or timer applied here that causes the thing to reset or lockup requesting reset of board??).

On investigating after the incident:

  • I can find no issues with my 12v30A power supply (12.18v measured on all three outputs)
  • None of the fuses on the board have blown
  • I can see no visual damage to the board (no obvious surface component failures, etc.) - but something very definitely blew on the board…
    The board now fails to complete a boot, with a blank display, and now shows a number of red lights on the board…

Was using a needle cutter (pictured) but powered from the PSU directly, not via an output on the Rambo Board.

All cables are insulated and stepper wires are all in drag chains (protected), only non fixed or enclosed wires were those of the needle cutter, and these were also not shorted, etc. as I was hand feeding these at the time (don’t have a wiring solution for this part at the moment!).

Rambo 1.4 (V1 supplied with 12864 display) with Steppers online 82oz NEMA 17 steppers (all still working fine - tested in different environment), Latest Marlin 2.0 software (dualendstops variant), SD Card used to load gcode files (Flite test plans converted suing EstlCam 11 software and Inkscape). Can supply videos of this all working fine, but too large to post here.

Where do I go from here???

What is the warranty arrangement on the Rambo board please?

Andrew (UK)


This is normal and happens when your gantry is more than 200mm from the end stop.


Those are all the mosfets showing “on”, never seen this.

I understand your frustrations but please have some patience with troubleshooting. The boards are all fully powered tested and flashed two times before shipping. they are extremly robust and mostly fused this is something I have never seen…but I also am not sure there has been more than one bad board yet.

You have already told me over email you are certain you have not flashed it with estlcam.

Can you unplug everything and reflash it with the stock firmware?

Looking at both sides of the board do you see any toasted traces or anything?

Any chances of metal debris shorting it, broken needle?

Thanks for the quick response,

Glad to hear that the X/Y homing is not an issue, etc.

Yes, board is stand alone operating from SD card, and has been functioning correctly until this point…

I will take a closer look at the board (remove it from the printed housing and inspect for obvious damage of a component/track).

I don’t see any chance of debris on the board - I’ve only been cutting a single sheet of foam to this point… and needle cutter did not break as still intact and operational (checked the length and still OK).

I’ll dismantle and take back to the house for re-flashing exercise, but have a feeling the board is not going to respond… lets see what happens when I try!


Update: Just removed and checked the board as best I can with a Loupe, and nothing indicated in terms of damage to either side of the board (that I can see).

I then tried to reflash the board…

It is recognised by my PC as a USB connected device, I can query the board and com port in Arduino environment, and get an appropriate response, but will not re-flash, and does not reset the red LED’s either. (Times out on uploading the code via USB).
TX LED was flashing most of the time, but I did not see the RX LED flashing.

I also note also that the largest chip on the board (ATMEGA2560) gets extremely hot (almost too hot to touch) after a very short period of time.

Think I am now at the limit of my abilities in diagnosing any further… Seems like something internal to the board has blown at this point…






That is not a normal upload error, did you have the board powered?

Sorry for being thorough I need to talk to Ultimachine about this. I guesstimate I have been through a few thousand boards now, and none of this is familiar to me. I want to know if they have any idea if there is a fix. Shipping is going to be expensive and take time so if they have a fix it helps us both.

Appreciate the thorough approach Ryan, as I’d rather a quick fix too!

Yes, board was powered on to re-flash, and it took some time for the message recorded to occur… Longer than if not powered on - where you get a timeout error… This was not the same. As per my note, I didn’t see a corresponding TX/RX sequence - looked to be one way to or from from the board.

I had flashed the board originally with the dual endstops image, and tweaked the custom name, etc (evident in some of my pics I think), and found this variant was working OK in the first instance… dual endstops working correctly.

Had printed the crown test, etc. done a few runs of some test just printing in the air at first, then moved on to a running needle cutter (powered directly from the PSU (not via the Rambo board) with an SBEC for drop down to 5v for servo tester (needle motor speed), and linked to a 20A ESC and HobbyKing brushless motor) Following these tests, I had just started to run some depth and bed leveling checks using a flitetest plan (.gcode file in SD card on the V1 supplied 12864 display board), which was going well.
Then during final stage of the print the board made a “pop” sound, the speaker on the unit played a squeak type of sound, and LCD displayed rolling garbage… just as I pulled the plug. Steppers were still driving at this point, till I cut the power.
I assumed the pop was a component blowing, but could have come from the speaker (as I just cant see any damage on the board at all). There was no smoke or other sign of any issue, just a blank screen and the RED LED’s all came alight when I turned the power back on again.

Looks like a part of the board is not functioning correctly to me.

As I mentioned, none of the fuses has blown (which surprised me), and the ATMEGA2560 chip now gets VERY warm - would likely scorch the board if left powered on for any time - it wasn’t doing this before that point (just slightly warm to the touch).




wondering what is happening please?


Send it back in. Keep your shipping receipt we will follow the standard procedure.

Hi Ryan,

Sorry I’ve been working away.

Can you confirm the return address please?

I am planning to return only the main board too… Assume this is OK as the rest is installed in housings and inside the tubes of the machine?

Please let me know if this is acceptable?


No problem.

Bottom of this page, https://shop.v1engineering.com/pages/refund-privacy-and-tos-statements


board was posted last Friday so should be with you any day now.
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Hi, can you confirm receipt of board please?


Thanks Andrew

It’s already on the way back you should have an email and tracking number.