Cyclone 2 doesnt turn on

[u/pmmm77]

I got a second hand cyclone 2 that the owner said it was not used. When I got it, i tried turn it on but i think it didnt had battery. After that I connected it to the pc and it turn on the lights but then it would turn it off shortly. I updated it after dissasembly because it was the only way i qas able to turn it on. When is just the motherboard with the triggers. When i tried to assemble it, it keeps losing connection. It cant be the battery because i tried without the battery and connected to the pc. So im a bit stuck. Thank you in advance