A520F unable / missing download mode

Samsung a520 f 7.0/NRD90M/A520FXXU2BQIE
CSC code OPV
It's unable to get download mode,volume buttons works,same home button,also power. After raplace button flex,same. JIG thru USB converter doesn't work,command adb reboot download in recovery mode also not.
Any idea?
Possible locked download mode?