Having read further in 'Sd2snes acting weird' thread - Akari is prolly correct here....
"The Super Famicom does not work reliably on the PAL power supply adapter. SFC needs DC, PAL SNES needs AC. They are NOT compatible even though the plug fits. A PAL SNES might run fine on DC though.
Luckily the SFC doesn't break even though it gets wrong polarity half of the time because it has a built-in diode to protect against inverse polarity.
However of the sine wave coming from the AC (PAL) power supply, only half of each wave actually gets through to the voltage regulator, and most of the time the voltage is too low (except at the times where the wave gets above +7V).
For low current situations (like original games WITHOUT SuperFX/SA1/etc.) and small number of controllers this might barely work out because the large electrolytic capacitor in the SFC manages to store enough charge. You might notice discoloration in composite video output or an overall hum in audio/video. But as current draw increases the console will basically run on a 50Hz pulse, crashing inevitably."