Stepper motors are not working when connected with RAMPS 1.4 ISSUE: Stepper motors are not working when connected with RAMPS 1.4.

OBSERVATION: The LED lights(LED 2,3,4) in the RAMPS 1.4 is not powering up.

PRACTICES: I use Arduino Mega 2560 and installed Marlin firmware in it. And I bought a RAMPS 1.4 in a local electronic dealer. I placed the RAMPS over Arduino Mega 2560. For testing I just connected 2 NEMA 17 stepper motors with RAMPS. When USB port connection is given from laptop to Arduino board, a LED light is ON in Arduino board (L) and in RAMPS (LED 1). I use SMPS 12&nbsp;V 20&nbsp;A as a PSU for RAMPS. But in RAMPS the LED 2, 3, 4 are not switched ON. I checked the input voltage to the RAMPS using micrometer and it shows 11.75&nbsp;V. But there is no output from the RAMPS.

Also I installed and tried Repetier firmware and Grbl but it doesn't work. And I use Windows 10 pro 64 bit OS.

When I flashed Arduino with Grbl, in this case all of the LEDs on the Arduino and RAMPS 1.4 are switched ON. I use Candle GRBL software to test the stepper motors.

And I replaced and tested with another RAMPS which is bought from Amazon but the problem remains unchanged.

Kindly give some suggestions at the earliest.

I have attached the images of my circuit connection:





 

Board selection in Marlin:

#ifndef MOTHERBOARD 
#define MOTHERBOARD BOARD_RAMPS_14_EFB 
#endif 


Additional clarifications

In response to Professor's questions:


Yes the stepper drivers are connected correctly 
Yes the stepper wiring is accurate (2B 2A 1A 1B) as per mentioned in the Ramps 1.4. 
No there is no voltage input to stepper motor. But there is 12V input to Ramps 1.4. 
Disabled cold extrusion 
No, the firmware is not set to no move before homing (issue G28 first) 
Yes, pins are set correctly for your board in Marlin
I actually thought the problem is in the electronic circuit but the problem is the baud rate. I initially took the baud rate as 115200 but later. after someone's suggestion, I changed it to 250000 and now it's fine.