Stephen Sank diagnosed the problem with my friend's Spectral DMA-200. There are several DMOS FET that are bad or about to go bad. I need 4 DMOS FET model VN0116N5 or VN0120N5. and then also need to replace 4 DMOS FET PN0116N5 or PN0120N5 that are probably near failure. Total 8 pieces. Does anyone know where my friend can source these? VNs are available but Sanks thinks that they are not authentic. Any help will be appreciated.