I have finally managed to repair my DX4000 unit with both onboard NICâs working.
Here is what i have done:
I have replaced both gigabit controllers (WG82574L) marked with pcb designators U23, U22.
These you can get from RS Components.
There are three power inputs which go into U23 and U22.
These are 3.3V, 1.9V and 1.05V.
The 3.3V is there to power the controller and the other two are logic supplies (I think)
The IC that i have charcoaled on the board (U17) ended up being a step down converter which had an output of 1.9V (which i worked out by using continuity test on DMM).
When i got the replacement U17 (RT8259) step down converter delivered, it didnt output 1.9V but 11V instead which lead me to believe that the resistor network which decided what voltage output is going to be was damaged.
So i used a custom power supply board which i wired in manually onto the PCB to give me the desired 1.9V supply for the gigabit controllers.
After putting everything together, i connected i the power supply, network cable and powered upo the unit.
Shortly after the powerup i have seen the very thing i was waiting for " an IP adress pop up on the DX4000 LCD screen given by my router".
Once again i have to remind everyone that the powersupplies that provide 3.3V, 1.9V and 1.05V are shared between both controllers.
If one controller goes bad for an unknow reason than it shorts out the power supply that is used by the otherne aswell. I still think that that if NICâs fail one should be able to access the data via one of the two USB ports provided.
Well, here is my 5 cents worth of experience, hopefully this information will help others that are still holding on to their unit hoping that one day they will be able to retrieve their precious data.