Help with Problem X axis Stepper Please

[GND]

Good clarification, John - I assumed as much but I was in a bit of a rush and didn't explain myself very well last night! The back of the chip is internally connected to ground, so if the designer of the equipment didn't insulate it from the common heatsink, then the heatsink must be grounded as you say. I'd argue it's not ideal practice, and that insulating the chips individually is perhaps preferable. But best just reproduce what the manufacturer did, as it seems to work. Unless that was the cause of the failure of course....!

Well spotted regarding the contacts - they do look a bit iffy! Those are "turned pin" type sockets - high quality ones, which is a good start. But definitely worth following John's suggestion to check them carefully, or even replace them. That of course involves soldering :-)

Graeme

[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