On Wed, 09 Mar 2016 00:20:35 +0100, Dimitrij Klingbeil wrote:

Good test. It would be more straight to plug the right voltage to make
it dissipate 2W, for 20 ohm that would be 6,3V and check what temp
results in 1 minute. You could use another identical resistor for the
test if you have one lying around to avoid unsoldering.


There's no need to unsolder, neither to actively avoid unsoldering. That
resistor is connected through a diode on the board. Just apply the
proper polarity signal, and the diode will take care of the isolation.

Thanks for the tips, guys, they will both save me time. I'll work out the
appropriate voltages for 3, 4 & 5W too and that'll save even more time.