Success! I repaired the one that failed last night. It wouldn't fire an atty at all. When you hit the fire button it would read low charge and show a blank battery even though the battery was fully charged. I was gonna disassemble it but couldn't find a torx bit or flat screwdriver to fit good enough. After trying to fire it 3 times it would turn off and I'd have to plug the charger in to reset it. I did it 3 times with the same result. I remembered that if they detect a short they will turn off and you have to plug a charger in the usb port to reset it. Also there have been ones that won't fire when you screw an atty down all the way if the grommet is bad. So I tried screwing an atty down until it just started reading the coil and tried it. It still wouldn't fire and still read low charge but I could keep doin it and now it wouldn't turn off. I then screwed it all the way down and it immediately turned off. At that point I could tell it was in the 510 pin, so I pumped it up and down and wiggled it for a couple of minutes. I put the atty back on gently and it worked. I screwed it down snug like I generally do and it's worked great now for over an hour. I believe there was a foreign metal shaving or something in it maybe from the manufacturing process as it has acted up since new quite a bit. I emailed my co-op guy earlier and he said he could get it replaced but I see no reason to now, for the time being. He also said that he has had no reports of failures from the second round of purchases compared to 40% reported faulty in the first round. So things are looking up for the 50s it seems. Sorry about the letter but I will continue to report on whatever happens. Thanks for reading.
That's great to hear Bike, especially given all the problems you've been having with them! I've had my 50 since mid February and [knock wood], haven't had any problems yet. If I do, wiggling the 510 will be the first thing I try.