Damage to printer?

I was changing up my printer's hotend, because it was leaking and while doing so I decided to check for any more problems. I heated the hotend without realizing my thermistor had not been attached, and the heater of the hotend started glowing bright red, I then immediately turned off the heater.
All the electronics still works fine as it seems, but could the overheating of the hotend heater have possibly damaged anything on the RAMPS board?

Also, does anyone know the correct way to power on your printer? My RAMPS 1.4 board is powered by a 12v 8.5A power supply, and right now whenever I use the printer, I always plug in the power supply first before connecting the USB between my computer and the arduino Mega board, is that wrong?

Hi,

If the ramps works fine (no red led lightened permanently), it's ok.
If there's a permanent led, change the corresponding transistor.
Be sure your hotend parts are not twisted or damaged by the overheat.
Be sure to secure the heat resistor and the thermistor to the hotend with Kapton tape.

8.5A seems light to me for a 3D printer. Mine is 25A.
With the 1.4 Ramps board, you can power both your boards with the 12V on the Ramps only.
If you print from your computer you'd rather plug you USB cable after turning the 12V PSU on.
I recommand to print from a SD card without connecting the computer.
The print is more fluent and faster this way, and there's no computer side issues.

++JM

Edited 1 time(s). Last edit at 08/25/2015 07:27AM by J-Max.

I found, when plugging in the USB connector first, the arduino board keeps cooler.
Reason is, the onboard regulator isn´t used then, even with 12V from the Ramps.
-Olaf

An 8 amp psu is plenty if you don't have a heated bed.