is any one here know how to diagnose this Sharp cash register that not power on at all,

i open up and check the FUSE (good) and replaced new internal battery so LUCK

please guide me to fix this

thanks

Hi.
It depends upon the model. If you replaced the internal battery without ensuring a power source at the same time, then you have probably lost everything in the machine. If you can tell me the model number, I'll see if I can help.

Mark