Unfortunately don't have any advice, but just want to say thanks for keeping these alive! It's a cool era of cameras that I think don't get enough love compared to the AE-1/FM range of SLRs. There's a Mirai near me that I'll likely be picking up soon. Given it's such an underdocumented camera, perhaps consider documenting your repair, perhaps also on a blog or somewhere more permanent than Reddit; you could really help folks in the future!