5i25 7i77 7i74/7i84, 7i71. Power up issues

Hi,
I think i may have a dead 7i71.

Tthe 7i71and 7i84 both are connect to a 7i74.the 7i84 powers up no problems and i can see it in linuxcnc however the 7i71 has no yellow power lite and I cannot see it in linuxcnc. I changed ports on 7i74 no dice, changed cable with the 7i84 and still no lites on 7i71 but the 7i84 comes up fine.

So this looks like a dead 7i71???

Thanks,

Bob

Looks like no VIN

PCW wrote: Looks like no VIN

Theres power on vin. Ill chck again tomorrow though.

With no vin on the 7i84,you still get the yellow 5v light.

Yes, the 7I84 has the cable power light, the 7I71 doesn't

The top yellow light on the 7I71 is run by 3.3V power
3.3V power comes from a regulator supplied by VIN

PCW wrote: Yes, the 7I84 has the cable power light, the 7I71 doesn't

The top yellow light on the 7I71 is run by 3.3V power
3.3V power comes from a regulator supplied by VIN

Yes I got it figured out. Seems the 7i77 doesn't like 5v vin power...lol.
I hate always being wrong......

Anyway, thanks, got everything up and running. Now on to tuning servo's....

Yeah the switching regulator for VIN has a high maximum input voltage (50V)
but that unfortunately also means it has a high minimum input
(it wont run below about 7V)