TDS3012B Ethernet connection failure

[Galen]

My TDS3012B and 3014B all can't connect computer through the network port on the back, using a crossover cable.
I acquired a TDS3012B with blank screen, after repaird (75.757 oscillator dead, use a 75M now), I tried the connection using the same cross over cable, it connected with no problem. So the cross over cable is good.
Then I switched this machine's power module (including some network circuit on it) to the no-connection machine, still no connection.  So the problem is not in the power module , should be in main board.
Of cause I copied the network setting in the scope, still no joy.  Ping shows no reply.

Problem solved.  This is caused by corruption NVRAM.  Use a good NVRAM file and burn in,  network works.