Mini Rambo 1.3a board keeps blowing 5 amp motor fuse

Good day all, i recently moved my mpcnc to a bigger enclosure, whilst doing a cutting job the machineissed steps, it track it back to a issue with d rails not being perfectly squared, so I took of the machine and square it, however when i restarted the machine i saw smoke from the rambo mini board so ill press the emergency button, and started to inspect d board, i saw that the 5 amps fuse responsible for motor control as blown, now when i replaced it with a new 5 amps fuse, the board keeps blown the fuses immediately, i even when i unplugged all motors and try it again, once d power is turn on the fuse blows. Has anyone had this issue or have an idea what is causing this?

If it’s still popping with nothing plugged in, then there’s something on the board that’s shorting it.

  • Check the steppers for stray wires at connectors
  • check for loose connections or damaged wires to the motor
  • check motor for free rotation
  • check stepper motor coils (both coils) for resistance to make sure there isn’t a short circuit

Might be a piece of stray wire, or chip in one of the stepper wire connectors on the board.

Thats my initial thought , so i cean the board and still not luck. The funny thing is the board comes on, wven the lcd comes on and works but not the motors and if i quickly bridge d fuse holder the board restarts

Can you post a good photo of the board?

It blows the fuse even with no steppers plugged in, so i can rule out d steppers and its wiring for now. I looked and cleaned inside the steepers plug mounts on d board all cleaned

Board might be toast then. If you post a photo of your board with some good light on it, we can look and see if anything jumps out at us to check.

Here is a picture of the board

I am thinking the same think but if its toasted woould d led boot as normal and i can even select print files and run the code, its just d move does not run, n it blows d fuses instantly

What’s the bottom look like?

I don’t know dude. That’s weird. Board looks fine.

One of the other guys might have some ideas once they see this.

Could shoot an email to ultamachine to see if they have any ideas.

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Sigh, this happen at d worst possible time, i just took the leap to rent a 20ft container to use as a workshop and transition to selling business signs since i am fed up of the 8 to 5 work

You said that you saw smoke coming from the board - pretty good evidence something on the board is toast(ed). And popping fuses with nothing plugged in that tells you too. Obviously, the challenge is finding what fried. The best lighting and highest magnification you can get will help. As best you can, inspect the components from the sides as well as the top. Considering there was smoke, I wouldn’t necessarily be looking for just blackened components - especially on the I.C.s. I’d also be looking for a grey area that might be smoke residue. Might sound strange, but your nose can be a help sometimes (yeah, yeah, toxic fumes …) One thing I see that seems a bit off is that quad flat pack labeled Q8? In your pic, it looks as if there may be some pitting (blow hole?) on the top. The other is that black component on the right of the fuses. Probably just because the pic of it isn’t very clear. Good luck.

Yeah. The smoke is probably causing a short. It may be something like a diode that cooked and turned into a short. I have had this happen and it can be very hard to find.

If you found it, we could help you figure out what part that was. Then you would have to order it, and then do the replacement. That might fix it, or whatever toasted it might just take out the new chip. Rework is also not a guarantee. Sometimes it works, sometimes something gets broken while soldering.

I think you should get a new board. The cheapest is probably a grbl uno CNC board, but there is a learning curve. The Rambo and SKR pro 1.2 are the easiest, but not cheap. Another mini Rambo would also be a good drop in replacement. You just have to flash it.

But I would consider reworking this board a side project now. If you can fix it, you’ll have a backup board. But your business needs to get moving.

I have order an skr 1.2 pro on amazon, wanted it from here bout v1 shop said its out of stock, and i need it now now, btw do i need to get d tdt 35 screen or is not necessary, i also bought 5 tm2209 drivers. Ill have to get a microscope to find dat burn component cus im not seeing any damage parts.

The SKR Pro will work with the 12864 smart controller, just no touch screen (Which is known flakey at times) functionality. We tend to recommend Marlin mode where the TFT35 E3 pretends to be a 12864 controller anyhow. Personally, I like the touch screen terminal mode though, and you won’t have that.

The TMC drivers are sweet though, Quiet might not mean much with a CNC, but the 32 bit processor on on the SKR Pro, you’ll also have fewer issues with arc commands in your CAM, so smoother finished projects, or at least smaller finished gcode files.

For the original problem… Blowing the fuse with the power on, becore enabling the motors probably means that it’s a component in circuit before the driver. I’d look at the components in the power conditioning circuit first. These will be near the fuse,

. Ill will try to look for the component but i dont have the skills or tools to do smd repairs., i will cancel the order of the new tdt 35 v3 s reen cus i dont care for touchscreen, ill put d $45 towards endmills. Once again thanks for the advice