Smoke Free 7i76

Hello. I wrecked my 7i76 and was hoping for some advice to keep the casualty count to 1.

I first set W2 to the right, and W1 to the left to connect VFIELD to Vin according to the manual. I attached 24v from a Meanwell power supply to VFIELD, then turned things on. I started PNCConf to play with the Y axis.

The Y axis would not move, so I took some measurements. I measured:
- 24.2 V across VFIELD and GND
- ~150mV across Vin and GND
- ~150 mV on TB2 DIR1, while I tried to jog both ways in PNCConf.

I assumed I was getting no 5V power. I tried W2 to the left and W1 to the right, with the same results. I came to the forum and saw this while searching: forum.linuxcnc.org/media/kunena/attachme...8/7i76_Anschluss.pdf. "Ah!", I thought. "VFIELD connected to Vin means it  *can* be connected, not that it is automatically connected." So I wired up as in the diagram, with 24v into VFIELD and Vin, and when I plugged it in I heard the lovely frying bacon sound.

Is my blunder obvious? It isn't to me.

Rod

The 7I76 W2 jumper needs to be set in conjunction
with the FPGA board's cable power jumper.

W2 left = 7I76 5Vi power is from FPGA card, so FPGA card
needs to be jumpered to supply 5V to the daughtercard

W2 right = 7I76 needs separate 5V supply and FPGA
needs to jumpered to _not_ supply power to the 7I76

It sounds like you did not have 5V initially.

W1 should normally be left in the left hand position

Not sure what happened, Is there obvious damage to any part?

Got some crackling and some smoke. Not a ton but some, and that sweet, sweet ozone smell. No dark stains that I can see anywhere.

I checked and 5i25 was set to supply power, thanks for pointing that out. If I have W2 left, should I be able to read 5V TB3 Vin? I was getting 120 mv or so, just floating I guess. Maybe the card was already damaged.

Vin is not connected to the 5V supply at all.
You should be able to read 5V at the step/dir connections

Both W1 and W2 are in the left position. The two jumpers on the 5i25 are both in the up position. (This was the configuration I started with, before I made it smoke).

I ran PNCConf, set up the axes, went to the Test Axis screen for X, enabled the axis and hit Run. +5VP (pin 6) was at 105mV with a bit of fluctuation. Same for all the pins including Dir0+.

It seems likely I damaged the board before I even started hooking it up (it's old, I had it on a different machine before.) Thanks for all your help, Peter, I'd never expect you to be answering on a weekend, much less Sunday.