A couple of my nsipre cx has battery charging issue. I guess the charging circuitry was gone. In the test mode, all the tests related to charging are failed. They are yellow border school property ones. I figured out the problem is on the keypad PCB board but not on the main top unit. Unfortunately I couldn't debug it or fix it, so I have to use it with a power bank and a cable. Anyway, anyone who has the same issue can just buy a $10 power bank and power it that way.