Help with Problem X axis Stepper Please

[howser37]

Thanks John, thanks for the warning about the fakes, could be i guess, just seems a bit too uncanny that it would blow so soon after the original non fake on that was in it as that was the original chip.

Im seriously considering building a new box from the ground up, if theres one thing i dont like its worrying whether the machines gonna blow up during a cut, especially as i cut expensive material usually so it can cost me big if it craps out.

Ive alwasy been a bit dubious about this control box to be honest

[GND]

Can't really add much over John's useful suggestions. It seems clear now that there is a fault beyond the chip - this second failure suggests the first chip didn't just expire for no reason. So checking for decent connectivity to each physical pin using a multimeter could be worthwhile. Ideally right to the motor connections, and to the other connected components on the board. Maybe an intermittent fault though, like a cracked PCB track, which may measure fine most of the time, but open up as things get warm.

Maybe it is time to get new electronics as you say? Particularly if the risk of failure is costly to you. I hate to waste perfectly serviceable kit, but sometimes pragmatism has to take over!

Cheers
Graeme

[howser37]

Hi Graeme, im pretty much resigned to the fact im going to build a new control box now, i do intend to build a new CNC myself at some point so it makes sense to get learning now and also i may well overspec it so that i can use it with my new machine when i get it built.

In the mean time i am wondering if it would be as simple as possibly utilising the spare driver in this control box as the second X axis driver, as there is a 4th axis driver in the box that is not being utilised as i do not have a rotary axis, not quite sure what would need to be changed in terms of settings as the other 4 drivers are on one board and the rotary is on a seperate board

[howser37]

Think i have found the likely culprit, looks like a cracked track on the back of the pcb, i will post a picture up

[GND]

Sounds promising!!

[howser37]

Here is the picture of the cracked track, is this repairable?. Definitely seems to be the culprit as it is on the correct chip and even leading to the correct area of the chip that has popped both times.

[GND]

Definitely repairable! I'd suggest you cut out that offending length of burnt track so it's not flapping around in the breeze, and then re-make the connection with a short length of thin solid core insulated wire. You're lucky in that it essentially connects two of the chip pins together, so you can use the PCB pads for those pins as end points on which to solder your little wire. Pull the chip out and d the work. Given a few minutes with the chip datasheet we could also work out which pin has become disconnected, and hence what the possible issue might be.

Now of course it could be that the track got burned out as the chip failed, and hence wasn't the cause of the failure - but more the result. Or indeed, has the chip actually failed? Could the board have failed whilst the chip is still OK? Looks like that track took a bit of an overload, but why is that?

Datasheet, datasheet....