I believe that the RAM is actually storing the fault however I won't pretend to be an expert on these boards. I have a lot of LRVS on my route and most of them never have any issue. I'm actually quite fond of the LRVS but they sure can be a pain to fix when it comes to the boards. Always seems like a guessing game. My most recent problem I had where this worked was a magnet that fell out of place and believe one of the induction switches picked up where it shouldn't have causing it to go fatal. The elevator was holding hall calls on all three floors and the car calls as well. After sorting through the prints checking relays etc. I went through the hoistway and found that magnet. Once I placed it back the elevator was still dead in the water. Even after leaving the power off all night same issue the next day. Checked voltage on power supply board, call board etc. I must say draining the capictor is never my first choice however I tend to do it before I yank any boards and send them off for repair. This time it happened to work. Obviously this route can save the customer a great sum of money if it works. I've had this work just a handful of times. Learned it from my boss he's pretty clever with 40+ years in the field.