burned OUT what about warranty ?

[Richards]

Doing self-repair of a circuit board without having full schematics of that circuit board is not a good idea. Components are sized by the designer to meet the electrical requirements of the circuit. A resistor does not just blow up. Having two resistors on different circuit boards burn up at the same time tells me that something catasthropic happened. It is very important to know why the two resistors burned up before replacing those resistors. Somehow either the voltage rose dramatically or the current increased dramatically. Resistors limit current to inputs and from outputs. If a resistor burns up, it's associated input or output was probably destroyed also also.

I have a fairly well equiped electronics lab with a 'scope, meters and 45 years experience designing and building circuit boards. When I fried the Acorn, I didn't even try to fix it myself. I didn't have a schematic for the Acorn and I didn't have diagnostic software to fully test the board after it was repaired. I knew that the possibility of fixing a serious problem by just replacing a component was slim.

[Martin Zarnay]

You totally right, when I've seen burned resistor that was the first thing crossed my mind. My friend who would do replacement taled me the same thing.

[eng199]

The burned part on the ACORN is a ferrite bead. EGND / mounting holes and COM terminals are supposed to be at the same potential on ACORN. EGND and COM were not the same at some point in time, causing the damage.

The BeagleBone doesn't have reference designators shown, but I think that is R137 burned up. It is a 0 ohm (jumper) from the ethernet transformer center taps to a PHY power supply rail. Burning this up means the Ethernet cable had some voltage on it that was not supposed to be there.

The ACORN can work without the ferrite bead. However, the size of the blast area indicates that there was high voltage involved and other parts may have been damaged.

I doubt the BeagleBone will work again from replacing the resistor. There was a large overload connected to a supply rail through that resistor. There is probably extensive damage on the BeagleBone.

[martyscncgarage]

Hi guys, I have a new experience with my Acorn, as I was using it and it suddenly stopped. I was wondering what is going on so I looked at the board and it was burned.

Do o you have any experience with it? I need to apply a warranty as it is still in,IMG_2028.JPG but don't know if I do that by centroid or supplier in EU I've bought it from, where it is faster?

[martyscncgarage]

Explain your setup. What kind of spindle drive do you have? What kind of drives do you have? Which schematic did you use?
You need to find the cause of the problem before you replace the board. To me, that looks like some thing external to Acorn went wrong and you'll likely burn up an other if you don't find the cause. No description of the machine, spindle drive, axis drives, pictures of the setup, wiring, specifics, can't really help in figuring the cause. And you really need to identify the cause....Eng199 is Centroid's E.E.
Been there done that....

Marty

[Martin Zarnay]

The burned part on the ACORN is a ferrite bead. EGND / mounting holes and COM terminals are supposed to be at the same potential on ACORN. EGND and COM were not the same at some point in time, causing the damage.

The BeagleBone doesn't have reference designators shown, but I think that is R137 burned up. It is a 0 ohm (jumper) from the ethernet transformer center taps to a PHY power supply rail. Burning this up means the Ethernet cable had some voltage on it that was not supposed to be there.

The ACORN can work without the ferrite bead. However, the size of the blast area indicates that there was high voltage involved and other parts may have been damaged.

I doubt the BeagleBone will work again from replacing the resistor. There was a large overload connected to a supply rail through that resistor. There is probably extensive damage on the BeagleBone.

I found that this is an R100 resistor, I did resolder that, a fast DIY solution so will see if I fix it. but nothing there must be more damage on board than that

[Martin Zarnay]

Explain your setup. What kind of spindle drive do you have? What kind of drives do you have? Which schematic did you use?
You need to find the cause of the problem before you replace the board. To me, that looks like some thing external to Acorn went wrong and you'll likely burn up an other if you don't find the cause. No description of the machine, spindle drive, axis drives, pictures of the setup, wiring, specifics, can't really help in figuring the cause. And you really need to identify the cause....Eng199 is Centroid's E.E.
Been there done that....

Marty

I do use standard NEMA 34 closed-loop steppers and huanyang VFD. and what schematics, I really don't know right now. it was over a year I did controller...
I will attach some pics when ill get to the machine tomorrow

[martyscncgarage]

It appears you have an early revision Acorn without the relay board? Did you connect the VFD directly to Acorn outputs or via a relay board that you installed?

Use a relay board to protect the Acorn outputs. Also make sure logic power supply Com and GND are tied together.

Pictures of your setup would be helpful.
Marty

[eng199]

I found that this is an R100 resistor, I did resolder that, a fast DIY solution so will see if I fix it. but nothing there must be more damage on board than that

The resistor was probably R136 then. 0.1 ohm according to schematic.
https://files.seeedstudio.com/wiki/Beag ... EEN_V1.pdf
It goes from chassis GND (ESD_RING) to logic GND (DGND). This would be damaged from a logic and chassis GND mismatch just like the ferrite bead on ACORN.

It is not going to be a warranty repair unless someone is feeling overly generous.

[Martin Zarnay]

It appears you have an early revision Acorn without the relay board? Did you connect the VFD directly to Acorn outputs or via a relay board that you installed?

Use a relay board to protect the Acorn outputs. Also make sure logic power supply Com and GND are tied together.

Pictures of your setup would be helpful.
Marty

It was connected to board relay not expansion relays ...