u/ExtraHousing4739

I found this old SONY diskman I plugged it in, but I don't understand why it's not showing signs of life.

Can anyone help me out? I would love to have it in working condition...

Also it did not have manual with it so I did not know how to troubleshoot. I tried putting batteries and plugging in and both same time but that didn't work either

How do I know it turns on also?

I don't understand this 3s bms thing at all because I just started electronics, so I need a connection diagram of sorts to connect my batteries to the circuit

I haven't bought it yet because none of the diagrams make sense

Please help me out😭

Also how do I solder batteries

I tried soldering them in series but solder won't melt on it, I'm afraid of it overheating

Also I don't have the nickel strip thing to connect batteries so I have no other option but to solder