MRD500

There may still be some around for purchase in small quantities but my guess is that the majority will be held by parts brokers with an MOQ of more than 1.

If you don't have any luck with finding the MRD500 then I would suggest a Vishay BPW24R

You may even try to get a sample

and if that doesn't work, one of their sales agents may be able to help. Also Google 'bpw24r'

Thank you very mach Ross, I greatly appreciate your advice. Regards, Alexander.