How to test RAMPs 1.4 & REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER

Hi guys,

I am not an electronics guys and am building a 3D printer with Arduino Mega, Ramps 1.4 and REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER. I loaded Marlin and controller worked whilst connected on the computer USB where I could run through the menus. I made all connections to Ramps 1.4 with XYX E0 & E1 A4988 drivers installed, but only steppers connected to XYZ & E0. I thought this was all in order, but as soon as I put power on, some smoke came from the E1 driver and I switched off power. On inspecting the installation I found I made a mistake by connecting +12V from 5A rail (supplied from external PS) on the + of all the end-stops (pictures on right of the Ramps 1.4 RepRap confused me a bit .) Further inspection showed that the Mega is not recognized by my PC, so I think it is done.

I am now hesitant to just connect a new Mega as I do not know if the Ramps 1.4 and Discount LCD 128x64 controller boards are still in working condition.
1.) Can anyone please advise me on how I should go about testing the Ramps 1.4 and Discount LCD 128x64 controller boards without blowing up another Mega?
2.) With the 5V fed into the + end stop pins, what can I expect to be toasted on the Mega? Is this repairable .......?
3.) If a A4988 driver is installed on the E1 or any driver connection without a motor connected to it, can one expect the driver boards to be toasted?
4.) Can one use the A4988 drivers on XYZ and DRV8825 on the extruders?

Thanks in advance.
Jaco

you have fed +12v into the +5v side of things, that’s very bad.

basically everything that was expecting +5v is very likely dead


First question is can you do SMD rework? if no, then the mega is not repairable by yourself. and they are like $9 from china, not worth anyone else time

1) I wouldn’t even try to check any of it... its not worth killing additional hardware. you need a good knowledge of electronics and a current limited power supply as a start..
2) everything that used 5v is now fried. the 2560 and the usb/serial chip, probably the 3.3v regulator, the lcd controll chip, the mosfets on the ramps...
3) it was using 5v, It was plugged in, its probably dead
4) yes, you can mix and match stepper driver any way you wish. Just make sure to get them around the correct way.

Thank you Dust.

Also - do not fit the stepper drivers if you do not have the stepper motors connected.... in your case you should NOT fit the E1 stepper driver..