Help with Problem X axis Stepper Please

[howser37]

Thanks John and GND. I will check the pins for damage

[howser37]

Just in case anyone else is searching the forums about a similar issue, i replaced the damaged driver chip with a new one and the axis is now working fine again. There was a small silicone pad on the back of the old driver chip and thermal grease so i used this pad on the new chip and applied MX4 Thermal non electrically conductive paste to the back of the chip.

I did check that all the socket pins were working correctly and were not damaged prior to installing the new chip. The only slightly difficult thing was getting the pins into the socket without bending them as they are quite delicate. I did several hours of cutting last night with no issues

[Clive S]

Its always satisfying to get something that was broke working again

[GND]

Nice work! Hopefully a one-time glitch that won't ever happen again!

Cheers
Graeme

[howser37]

Oh well, bad news its gone pop again, machine was not even cutting at the time just idling then pop and burning smell, opened up the controller and the same chip has blown again (the new one).

Any ideas what the most likely culprit could be ?

[john swift]

if the replacement TA8435HQ was not a fake / factory reject

then it could be an intermittent break in the motor cables or connectors

damage to the current sense resistors and the PCB tracks
if the reference voltage to the IC is adjustable
the preset potentiometer may of become intermittent

plan B could be to unplug the stepper IC and connect a single axis stepper driver board to replace the faulty axis drive

a TBH6064 board will be a better choice than the infamous TB6560

John

PS
http://sound.whsites.net/fake/counterfeit-p1.htmS

[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