radio trouble 01 tahoe

[claxy01]

radio will not turn on checked fuses and changed factory radio to another factory radio

 

[kynobi]

I have the same issue-
2001 tahoe z71 and the radio does not work- after checking the fuse I purchased a used oem radio and installed it
the clock display comes on until I hit any button then the display goes off.
the replacement also does not work but the unit is getting power because the clock briefly displays.
Any idea as to the problem or where to troubleshoot next?
thanks