Just starting with a new Mega 2560, LED never become green just yellow, further question, which DC and polarity is supposed to apply on the power inlet?, trouble shooting ask for changing a jumper position, but there isn't any.
LED color is irrelevant
center pin is positive, and you should be able to measure raw power voltage on the Vin pin
run an example program from the SD library and watch the results on the Serial Monitor to verify the unit is alive. it does not matter if you have no SD module, you just need to see a response.
Thanks, it works fine. I underestand that the DC power is positive at center lug, range? just 5 VDC?, just a question about SD, should I connect it to ICSP connector? there is a reset lug instead of CS
I do not exceed 9 volts on my cheap chinese clones
SD cards use pins 50 - 52 on a MEGA. pin 53 CS can be an input, if you pull it low. the MEGA becomes an SPI slave, not a master