WD seems not to provide any replacement power supplie for the WD500E035 anymore.
With a bit of handicraft work I’ve found an alternative way to get rid of this.
I bought a JHS-E02AB02-W08A from Pollin, cut the cable in the middle, interchanged the yellow (12V) and the black (GND) cables but left the red (5V) connected. Then I removed carefully the sixt pin of the DIN connector which isn’t used for the harddrive.
That’s it - the drive is running again.
An even cheaper approach would be the “Navilock extern 240 V > 4 Pin Molex 12 V / 2 A” for about 10 Euros - Google will help you to find it. Then simply reuse the connector of your old broken Power supply.