hopefully you have already replaced the PSU with a higher quality trustworthy model so as to not risk the rest of your components.
once your PC is safe again with a trustworthy PSU model;
you can just reconnect the drives via their SATA connection and try other recovery softwares to see if a different application may be able to recognize the drives.
some of these data recovery applications may have trouble discovering drives that are connected via USB.
if the drives' circuits are blown there is nothing you personally can do to recover the platter and any data that still may be there.
you would have to find a local PC shop with the proper tools or possibly a larger chain store that offers these types of services.
but, that depends on where you live.
you would need to search and ask around to find somewhere\someone who can guarantee recovery or no fee.
some places will charge a flat rate before hand and then do absolutely nothing and just claim they tried.