LAN/NIC problem

[cdslashetc]

The crosstalk is ON THE BOARD. If you improve SNR getting into the traces on the PCB it may improve just enough to get it to work.

Sent from my Nexus 6 using Tapatalk

No doubt.   There is an array of caps and resistors on the board near the RTL8211E chip; and lots of cold solder joints on the ones on my three boards. There are differences in these devices between the three boards... and some of the 000 values (devices that look like a resistor, but have zero ohms) are soldered straight across on one of my boards with cold solder joints !  I honestly think the problem is a cap or solder problem, if not on the RTL8211E chip itself, perhaps on the 'mods' field of resistors and caps near the 8211E.  

If there were cross-talk on the board itself...   what is your test procedure, and what is your solution?  Do you have some empirical test data to share ?

I say it's on the board since it doesn't make sense that the crosstalk problem would be on the cable if it's up to spec, exception being if the NIC is out of spec and overdriving the signal, but that wouldn't be the cable's fault. I'm getting ready to try some 1 ft CAT7 cables that arrived yesterday, these are STP of course rather than UTP so if there's overdrive could help with that, they have grounded boots may try tying to a common ground.

At my previous job working on a traffic management network I had access to very nice Tektronix oscilloscope designed for datacomm but not at my current job. But I almost forgot I have PocketEthernet--it's a bit buggy but hard to beat the price for what it does. Not sure what info it will give me, will give it a shot once it's finished charging.