help MKS Gen-2Z V1.1 blowing stepper drivers

hi im haveing a problem with my MKS Gen-2Z V1.1 it keeps blowing stepper drivers i check the stepper driver supply voltage on the board and its over volting them there hiting 8v on the 5v trace that feeds the stepper drivers i was wondering what chip regulates the 5v to the steppers i want to repair the my MKS Gen-2Z V1.1 but need some info on the board circut diagram whould be nice as well thanks

Hi mario_pic.

Have a look on your MKS Gen board for two small surface mounted electronic parts labelled LG1 and LG2. Get your multimeter and measure for continuity (or ohms) through each one. More than likely LG2 has gone open circuit.

LG2 provides the ground/0 volts connection for the stepper drivers. Without the ground, the stepper drivers float up to a higher voltage from the motor supply (12V) and then will fry the chip on the stepper driver. I had the same problem with mine and just soldered a link across LG2 to fix it.

PS: LG1 & LG2 can be located near the USB socket.

Hope that helps.

Edited 1 time(s). Last edit at 07/08/2015 07:19AM by gjt211.

Lg2 has 00.4ohms
lg1 has 26.40kohms

so i guess lg1 is open then also is lg1 smaller then lg2 just wondering if i got the right smt part also so i just jump it also wondering can i use a 0 ohm smt resister

well it worked put a 0 ohm smt resister on lg1 and its working thanks for the help

Hi Mario_pic,

Congratulations, you fixed it. Sorry I didn't see your previous post about whether you can use a 0 ohm resistor. That should be fine, but I caution you that the current flowing through the 0 ohms resistor can reach several amps. Make sure (check the resistor datasheet) if it can safely carry the high current. I just soldered a bridge (small piece of wire) directly across the two pads.

PS: I have replied to your PM.