My friend the Yashica/Kyocera repair guy says the original RTS (the RTS I) is a mess as far as the electronics go and they're mostly unrepairable today. Not so with the others, though I waited 7 years before he found the right spot to send my RTS III in Japan for repair. They had to replace the internal displays in mine to get it operational again. Works great now. He says the RTS II is an RTS I with better internal electronics design inside.