by cncdrive » Sun Apr 25, 2021 7:36 pm
OK, I understand. Then it is probably that your 5V powersupply has a problem.
The overcurrent protection IC is directly on the 5V input before anything else.
So, if an overcurrent occurs anywhere in the circuit then the IC latch protects the circuit, so the board will not damage.
This protection is useful, because there were several cases when customers overloaded our other motion controllers' with shorting pin26. of the IDC connector to the ground, but that pin is the +5V and not ground and so if the powersupply is powerful enough and does not have a short circuit protection then this could damage/melt PCB tracks.
But this IC cannot stand overvoltages, so if an overvoltage is input to the 5V input, I think it is 6 Volts max. then the IC damages.
The good thing in the bad is that the IC still always protects the output even if it gets a high overvoltage and damages.
In other words it damages in a way that it still not outputting overvoltage on it's output, so the expensive logic parts on the board will still not damage.
However the board will not work anymore and the IC has to be replaced or bypassed.
It is easy to bypass the IC with a piece of wire from the input to the output, but without the IC there will be no more overcurrent protection.
It is also possible to replace the IC if it did not burn the PCB too much.
And I would also check that powersupply, because if that IC damaged means that the powersupply is not OK, it gives overvoltages.