7i76e Communication errors

Not temperature. Everything staying very cool and the error sometimes occurs within seconds of turning on.

Would it be worthwhile to test a dedicated 5V supply on P3?

Just noticed this comment.
I thought you were meant to use a direct connection between your PC and 7i76e (eg. ditch the hub) but I'll leave it to PCW to advise.

By temperature I dont mean high temperature, I mean a thermal intermittent, that may happen as the board warms up when first powered. The error is not Ethernet related.

PCW wrote: By temperature I dont mean high temperature, I mean a thermal intermittent, that may happen as the board warms up when first powered.

I don't think so. I've left it on for hours and can't see any difference in behavior. My gut tells me it's hardware but not necessarily the board. Right after the conversion it was running very reliably so it 'feels' like a wiring/configuration/connection problem.

My inclination is to try to change things and see if I can get the symptoms to change enough to give a clue. That's why I asked about dedicated power on p3.

You can certainly try but the symptoms don't really suggest a full 5V loss
(that would cause loss of the Ethernet link), but just a problem with the on card
serial link between the FPGA side and the field I/O side

Another possibility is field power dropping out for a short time

So I would check the connections on TB1 and if you want to try applying 5V to P3 make sure you
disconnect your 19V power from TB3

another thing to try is an alternate field power supply

I just received a brand new 7i76e (ordered & delivered in Jan 2019) and am getting the exact messages as sliptonic:

hm2/hm2_7i76e.0 smart serial port 0
hm2/hm2_7i76e.0 Smart Serial Comms Error: There have been more than 1 errors in 10 thread executions at least 200 times.
hm2/hm2_7i76e.0 smart serial port 0 local error = (3) Timeout
hm2/hm2_7i76e.0 smart serial port 0 local error = (13) Communication error

As soon as this happens the CR1 led goes on and CR2 led is never one. CR3 through CR6 continue to flash.

My W1 is LEFT (single power). I have 24V connected to TB1 (pin5+, pin8-) and TB3 (pin22+, pin23-) show in attachment. There are no other connections on the board yet. I do measure 5V across stepper signals (such as: TB2-1 & TB2-6). With scope attached I have never been able to see any pulses on the step or direction pins.

I am always able to ping the board with no problems and when I run mesaflash with --readhmid I am able to read data from the board and it does seem to have swversion 14. I will post that along later tonight when I'm back fiddling with it.

I have had these errors from the beginning and I have never gotten this card to work. This is my first time working with linuxcnc and any mesa card so my natural inclination is that I'm doing something wrong. This is the only thread that I have found that even mentions these Serial Port 0 errors.

Can anyone think of something else that I should check before I call Mesa?