Make sure you use a non polarized capacitor like the orange one shown in the left picture. If you use a polarized capacitor instead, you might get it backwards. If you hook up an electrolytic capacitor backwards, the electrodes oxidize and it starts to conduct current. Throw away any polarized capacitor that you hook up backwards. You can also use RST and BAT since it's easier (IMO). I heard the new M5's don't need the cap but I'm waiting for a new one to arrive to confirm.