Check if the charging port in the tablet is damaged or if the charger will not fit into the charging port. Check for corrosion on battery. Depending on how old the battery, it might be bad and need replacing. Look for damaged wires within internal circuitry. Also, Corrosion on motherboard may lead to your tablet failing to turn on. In this case, return it to the vendor. For more information check out the troubleshooting page.