Mesa 7i76e damaged expansion port?

Hi Guys

I am currently building my first Linuxcnc powered milling machine and the problem i`m facing now led to the first forum post in my life.
I use a Mesa 7i76e and added a 7i85 for the encoders. A while ago, I have set up all the servomotors and could even get them to run with the encoder feedback (encoders only update the DRO for when i want to mill by hand, without the motors). 
Unfortunately, a live wire touched one of the two boards and a bit of magic smoke got released. I didn`t see where the smoke emerged and i don`t see any damage on either board (but the amount of smoke should indicate some visible marks). Now my Encoder counts don`t get recognized by the Mesa cards. This is my current situation:

- I watched halshow and neither rawcounts nor any other counters see anything. 
- The encoder on the 7i76e still counts correct. This let me believe, that the encoders and wiring are good.
- The .hal file should be of no concern to me, correct? Halshow shows all 5 encoders but only Enc04 on the 7i76e counts.
- I bought a new 7i85s (7i85 were not available) and the new card doesn`t count either. (I flashed the correct bitfile)
- I put the 7i85 as well as the new 7i85s on the second expansion port and neither of them counted. (I flashed the correct bitfile)
- I tried to use one of the stepgens on the 7i85s but got nothing. (Tough, this one could be on me with a wrong configuration)
- I unfortunately don`t have another ribbon cable at hand. Is it possible, that the cable got damaged? I doubt it.
- The jumpers on both cards should be set correct (to RS422, power supply via exp port) and haven`t been changed since it worked in the beginning.

My question: Is it possible to force a sign of live out of the 7i85? Or somehow get proof, that the card gets "recognized" by the 7i76e? I would like to avoid unnecessarily buying a new 7i76 since they are hard to get and pretty expensive. Can I test something with a multimeter?

I`m grateful for any thoughts or ideas. However, my knowledge about electrical circuits is pretty shallow and even worse around software stuff (I hate Linux with a passion even tough I love the idea of an alternative to Microslop).

Thanks and greetings from Switzerland

P.s. I saw another post and it seems there is a terminal comand where you can force some response or a dump of specific components on the card. But I really didn`t understand anything going on.

You can do a quick check of the expansion port condition with:

mesaflash --device ethernet --addr IP --rpo 0x1004
for P1
and:
mesaflash --device ethernet --addr IP --rpo 0x1008
for P2

Where IP is 10.10.10.10 or 192.168.1.121 depending on 7I76E setup

Both should respond with  0001FFFF (with nothing connected)

Typically what would be damaged from this kind of a fault would
be either U3 (P1) or U20 (P2) = 74CBT16211CDGGR

P1 (U3) damage may show up on P2  (U20) as the chips share a low current
4 V power supply and a damaged chip may short this supply so the undamaged
one also shows a fault.