pilotphil

This is my first post. I read the rules but apologize in advance if I violate any protocols. I'm enjoying my Feelthere PIC 737 EVO but have a recurring issue with the aircraft experiencing a total system failure in flight. Typically this happens on approach after flying for 20-30 minutes. I'll be on final and a Master Caution appears and indicates an electrical issue. Very quickly, I get the klaxon alarm and everything shuts down. FMC and instruments all go dark. This leaves me flying a large glider at 3000 AGL. I'm stumped. I think I'm following all the check lists and everything seems normal right up to the failure. Any thoughts would be appreciated. FSX SP2 Dell Intel Core i7-6700 CPU @ 3.40 GHz, 16 GB RAM, Windows 10 (64-bit)