RAMPS extruder output broken?

Seriously guys,

I really start to be at war with electronics. Whichever project I start, I always end up having trouble with the electronics...

I got a RAMPS 1.4 board with Repetier firmware running with Repetier host. The first thing I noticed was, that the power terminal for the first extruder is broken, particularly one screw, whose thread won't grab onto the spring clip. Thank you, China.

So I hooked everything up to the second extruder terminal and changed the pin layout at Repetier, that all pins for the second extruder are treated like it's the first one.

Then I tried to heat up the hotend... nothing happens. Wow. I wired the hotend to the heatbed terminal, the hotend heats up and the thermistor shows the right temperature. Ergo the hotend is not damaged.

In Repetier host I activated the second extruder terminal without anything wired to it and hooked up a multimeter... It shows something around nothing and 0,15V, the red LED is just showing an almost invisible flickering, while it should be something around 12V.

So anybody an idea what could be broken or how to fix this?

I would redo all your solder joints in the following places on the RAMPS board:

Pin D9 (from the Arduino).
FET Q2.
The D9 connector.

BTW: If the + pin on D10 is broken, you can just use the + pin on D9, while using the switched (-) pin on D10. Both the + pins are wired together, so you should always have your PSU voltage on those pins with respect to the PSU ground (worth a check).

Other Q's: Do you have power on the 5A input? This runs the motors and both D10 and D9. The 11A input runs D8 only (as the heated bed draws a lot of current). You need to supply volts to both the 11A and the 5A input to get it working.