HELPE ME LN40C550

[kakaka]

help
I replaced the motherboard and the LN40C550 lost my USB and the TV does not connect the NETWORK (MAC ADDRESS FAIL).
what can this be?
Could someone help me?
If there are errors in writing, sorry, I'm Brazilian.

[saazao]

I have the same problem
replaced the main board
get "MAC FAIL" adr set to ff:ff:ff:ff:ff:ff
USB is working
Already did the factory reset via the service menu.
no change...

Anybody got something for this problem ?

thanks in advance