On the nearly identical U680 it comes back to life with a new regarcheable battery, don't know why U600 wouldn't. Try putting it in the sun, I have had some other calibers not come back to life immediately after replacing the rechargeable battery.
Which battery did you order?

 

Try putting it in the sun, I have had some other calibers not come back to life immediately after replacing the rechargeable battery.

Hot damn!! It’s back up and running, as you said it didn’t come on right away so I just closed the case back up after checking the battery twice and making sure it was in place and had voltage on my multimeter. I put it in the window and went to bed, this morning it’s blinking and actually working!

Going to try an all reset, zero in the indicator positions, and see if it will set time with the atomic clock! I was really worried I did something stupid and bricked the watch when it wasn’t coming back, but seems like it just needed to get the system going with a little charge.

oh and in case anyone else comes across this post with the same issues, I used the 295-6900 battery with the negative terminal tab soldered on the bottom. It was at about 80% charge in the package so it didn’t need to be “charged” before it worked, but for some reason the system needed to see some voltage coming from that charging circuit before it initialized everything else.

thanks again for all the help!

 

Yeah, I had a scare too when it happened with that other caliber. But with the U600/U680 you should be good until you get the ERR message. I have a U680 that keeps going back to ERR even with a new battery and all reset. So I just retired it.

 

I got two watches in the same lot, this and a caliber 2100 titanium, that both had the same backstory and issue: left in dark dresser for a decade and now don’t function.

I did the caliber 2100 first because it was a screw back, and thought it had the more complicated battery replacement with a screw down battery cover, it just immediately jumped to 75% on the power reserve and worked fine. So when it came to this one, I had a mini heart attack lol.

it wouldn’t have been half as bad if I didn’t spend 25 on the battery, 150 in case opening tools, and a week of my time tinkering and learning about this thing to get it open without causing damage in back up and running. BUT - it was worth the tinkering, tools, and wait 👍👍

 

The power reserve is usually not very trustworthy if the battery is bad, it will go to full in a few hours and back down low the next day, so you might still need it.

The Promasters with press down case are the worst, almost impossible not to damage the edge without super expensive tools. I'll take the screw down caseback any day.

 

I think the spring on the movement has to touch the caseback. If it doesn’t, the watch wont work.

 

The spring is there only to transmit the sound of the beeper.

 

I see it now. Theres a piece bent up on the movement, if THAT doesn’t touch the case back then the watch won’t work. My mistake.I just went through the same thing with my Campanola.

 

Sometimes they still won't work for a few minutes or longer after closing the caseback, so that is not it either.