Before you attempt to diagnose ANY hardware anomaly you need to be sure the software/firmware is working. Getting a fresh copy of Raspbian is a way to ensure that.
Microprocessor, Raspberry Pi & Arduino Hacker
Mainframe database troubleshooter
2012-18: 1B*5, 2B*2, B+, A+, Z, ZW, 3Bs*3, 3B+
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