''If the tablet isn't indicating that the charger is connected'' you may have to open it up and check if the DC-In jack is OK or not, i.e. ensure that there's power getting from the input of the jack to the output connected to the board.
Sometimes with these types of connectors the inner connector breaks internally and this opens the +ve leg of the power supply. The jack cannot be repaired, it has to be replaced.
''If the tablet is indicating that the charger is connected'' but the battery is not charging it may be a faulty battery.
Hi @billcornwell
''If the tablet isn't indicating that the charger is connected'' you may have to open it up and check if the DC-In jack is OK or not, i.e. ensure that there's power getting from the input of the jack to the output connected to the board.
Sometimes with these types of connectors the inner connector breaks internally and this opens the +ve leg of the power supply. The jack cannot be repaired, it has to be replaced.
''If the tablet is indicating that the charger is connected'' but the battery is not charging it may be a faulty battery.
Here's a couple of videos that may help.
[https://www.youtube.com/watch?v=Lx17DMmBMlw|JXD 7800B disassembly]
[https://www.youtube.com/watch?v=qZkV-RU9av0|JXD 7800B battery replacement]