Retrofit of Precix 5x10 CNC

No, If W4 is down, DB25 pins 22,23,24,25 are grounded on the 7I92 card.

If you made a jumper mistake and used a non-current limited 5V power supply,
you could have caused an open somewhere in the cable power circuitry
( it may also be the you are not looking at the correct pins, all I/O pins will read 5V
if the 7I92 is not communicating with LinuxCNC )

As a general rule when first setting up things you should use a current limited power supply
so a wrong connection cannot cause damage. Never use a PC power supply for this as
they can often supply 30A to 50A which can destroy PCBs if a mistake is made.

A very easy current limited 5V supply can be made from a USB cable with the small end
cut of and just the red ( +5 ) and black ( GND ) wires used.

What smoked on the 7I77? if it was something other than W5, it may be another issue.
(I would expect W5 to overheat if the jumpers were wrong and high current 5V was applied to the 7I77)

Dang!!

Well I was using a PC power supply, so that must have done it.I mentioned that in a post, and was hoping someone would catch me making a (apparently) stupid mistake like that. It always read about 5.05v to 5.1v on my meter. I understand not current limited...

Pin W3 and W4 were definitely in the down position, I made sure they were before applying power. Tripple checked it, because when i initially read the manual, I read the warning and didn't want to get that wrong. When it smoked I figured I did it upside down or something, but when I took it out I placed it right by the manual diagram.

Oh, ok, yes, probably because it wasn't communication with linuxCNC so that's why i was reading 5v...

Since this unit will be 12 or 15 ft away from the computer I guess I will buy an extra long USB cable to supply power to the 7i92, should I use another usb cable to supply 7i77? and you are saying from the computer's USB port to the 7i92 and 7i77 power connections.

Yes, the W5 smoked for sure, and I thought someplace towards the center too, but couldn't see any damage from a quick look.

How should I proceed?
I will get some extra long USB cables to supply power.
Power up 7i92 and make sure it's connected to LinuxCNC then check I/O pins for 5v?

If W5 smoked it does suggest that it was not in the right position
I would go back to you original settings (7I92 W4 UP 7I77 W5 LEFT)
and power temporarily with a USB cable and see if everything is OK
(after replacing W5)

I suggested a USB cable for testing but its not the best for operation.
for operation I would use a 1A or so 5V DIN rail supply or similar
(to maintain electrical isolation of the 7I77 encoder and Analog section from the PC)

Update: I went to move the jumpers and noticed they were melted. I moved the 7i92 to the up position and the 7i77 to the left positiion.

Powered the 7i92 (like it was powered and working before) this time with a USB cable from the computer and the 7i92 lit up, but the connected 7i77 didn't show any signs of life. Checked everything several times and was about to give up. Just for the heck of it I replaced the jumpers on the 7i92 and the 7i77 had some lights come on.

LinuxCNC still didn't open, but the log did say it found the 7i92. I ran out of time, but will dig more into it tomorrow.

I made my connection cables to go to the DB15 cables that went to the encoders to the screw type connections on the 7i77 and same for the servo drivers. I have yet to connect to any of the limit switches and other input and output. Since the power supply that is powering the servo motors is 48V i will not connect that to the field power of course. My question is since I am now powering the 7i92 and connected 7i77 through the USB and that is working fine, what would you suggest for a field power supply. When I initially came up with my game plan, I was going to use the PC power supply for the 5V for the boards, and the 12V for the field power supply, but since you told me to avoid the power supply (I'll bet that 12 PC PS is about 10amps) I am now wondering what you would suggest for testing the FIELD POWER in/outs? I got a whole box of transformers, would like a 19v laptop power supply running 3amps be a good power supply? or should I am for something less volts and/or less amps?

I am really careful with this board, and if it's still OK, I don't want to jeopardize anything going forward.

Thanks PCW for the help, and thanks for anyone's input!

I would use as low a current supply as you have for initial testing since a hefty power supply an a wiring mistake would be bad.

( only 400 mA or so is needed at for the 5V and less than 100 mA for the 12/24V field voltage)

The laptop supply should be OK for the field voltage, just make sure you have the polarity correct