I found my problem, which occurred after replacing the battery. From outside the watch there are only three buttons on the right side of the watch. Inside there are three on the left and right side. There was a slight/random connection on the left side from the middle button. Fixed that and watch runs with the new 3.7V 453030 400Mah like charming. Charged and synchronized serveral times.
Original: 3.7 V 442830
Replacement: 3.7 V 453030
The Pins move out! Like described above, there is one side with a larger head of the pin. This is the side where the pin comes out. The smaller side is where you push. Due to water and sweat, there is some kind off corrosion or buildup around the pin.This is why it does not come out easy. Important is to use right size of the tool. Lubrication with WD40 silicone oil helps.
look for a 453030 on Aliexpress.com.
it takes about 4 weeks from China and is with shipping 10usd.
it fits perfect. A 503030 does not fit
I changed the battery for a 453030 3.7V with 400maH. The battery fits perfect into the watch, but the watch does not power on any more. The battery is charged fully. I can switch on the watch with the power cable attached, I can Softreset and Sync it with the cable attached and also Reset to factory settings, but as soon as I detach the cable, the watch is switched off. It also recognizes the battery and reports 100% charged. For me it does not look like a HW defect. The watch even does not switch on when the old battery is soldered back.
Is there somebody aware of any SW change in some newer Firmwares of the watch? If some of you replaced the battery without trouble and some have issues, there must be something different in HW or SW. I have one of the “new” watches with already a cap on the charging connectors and I use the latest Firmware available.
There are people out, asking if a 503030 would fit, which I definitely can deny. 4.5 mm in hight is the max and about 32mm in length and 30 in width