7i84u probably toasted

We making progress but looks like I smoked the 7i84u.

One of the wires from a set of prox sensors, PNP NC, came out of the terminal and touched the board and now I've lost communication between the 7i96s and the 7i84u.
It powers on, CR2 and CR7 light up green but the red CR5 never comes on at all and there is no activity on CR6.
The card doesn't show in the HALmeter (I'm pretty sure I had it under the pins section when I was testing these sensors)

As far as I can tell the 7i96s seems fine, I'm hooking up some steppers to test and make sure

Anyone know if there is there anything I can test here? Not sure if it's worth sending back for repair or just buying a new one (i'm in canada, not going to be cheap to send for repair)

M

Do you have a thermal imaging or infrared camera or do you know someone who has one? Defective ICs often get hot when you apply power to them.

You might check if there is 3.3V (measure from W1 pin 1 to 3, pin 1 should ++3.3V)
Lack  of 3.3V may mean damaged 3.3V regulator or shorted part.

Nothing like that around me. The LV4051A chip closest to that area of the board has a bulged up spot in the middle and it's a multiplexer so it's probably toast but since there's no sign of any connection between the two boards now it must have taken out more upstream of that. I'm just hoping it didn't kill the communication part on the 7i06s
M

You might check if there is 3.3V (measure from W1 pin 1 to 3, pin 1 should ++3.3V)
Lack  of 3.3V may mean damaged 3.3V regulator or shorted part.

M
 

As I mentioned in our email communications, the 3.3V power supply may be shorted out
by the damaged chip (there may be more than one unfortunately). So if that is cleared,
communications may work. Also as I mentioned, damage to the I/O section of the 7I84U
is unlikely to propagate to the serial interface side as that is galvanically isolated (2KV!)
from the I/O side.

Just received the other email, (didn't make the connection to you)
I'll try as you suggested, nothing to loose at this point.
Thanks so much for the help
M

With the jumper removed, connected to field power and the 7i96s connected:
Nothing between 1 and 3 pins on W1
22.8v between 1 and 2, nothing between 2 and 3

carefully removed the IC, still nothing between 1 and 3 and the status lights are still the same.

Ah well, it was an expensive evening
M