Hello,
I have a DK Electronics shield on top of a Arduino uno.
I am using external 12V 2A power directly to the motor shield (I can also measure it as 12.1V at the motor shield power input).
I am trying to power a 12V case fan, which I have connected to the M4 terminal.
When I do the test, it only outputs around 5.5V and not the required 12V. Only the fan LEDs light up, but the fan does not turn.
What could be the issue?
Thank you
That outdated shield is based on the L293 chip that drops the supply voltage by several volts. Try 16V instead of 12V but watch for excess heat caused by old technology.
Modern MOSFET motor drivers provide much better performance.
Thanks for the reply, I did not expect it to drop by THAT much. I will order the v2, thanks!
neportocala:
Thanks for the reply, I did not expect it to drop by THAT much. I will order the v2, thanks!
Check and see what motor driver IC it has on board, if it is a L293 or the like forget it.
Look for a driver module that uses MOSFET technology.
Tom.... 
It's L293D, yes. Ordered a v2 clone, thank you!