sorenb

you might check the current sources:

I might have two sets I want to depart with 2mm/4oz

<10V offset isn't a problem. Engaging the servo should quickly get you <1V

lower the tail resistor by some ~50ohms and re-adjust

seeing only a few people have signed up for Carbon boards. I have some version 6g from PCBNet 2mm/3oz, that I don't mind departing from (16.75USD/ea). If interested shoot me a PM.

....same source as for the other 10m90's in your build?

where did you get those 10m90's from?

unless you've got bad 10m90's (I've never come across any) I find it peculiar that both seems to be acting up pull out one 10m90 and test it with a DMM at ohms, test drain-source: short all legs, before measure drain-source => very low ohms if you don't get that the 10m90's are probably bad if you have a breadboard you might find it useful to build a cascoded css including the trimmer, and test as previously described. If you can't adjust the current using the trimmer, the DN2540 is probably bad (I've seen that a few times) Or you can use an 8pin IC-socket with resistors+trimmer soldered to build a bug-style test CCS-fixture. .

Very nice build Jose con grat!

Yes, check your rectified input voltage ...probably too low ...or you might be pulling too much current >3A or so

not sure how you can measure currents like that using 18V ....sounds like something else is wrong ...

detach the HV rails and use the +LV or two 9V batteries

Have you checked the rail as described in the link I pointed to above?