Electronics Gurus

HV Op-amp question. Its driven by a -10v - +10v input. Output range is -80v - +80v. Being fed by -100v and +100v.

It is constantly putting out -45v, with 0v on the input. I suspect it lost the +100v.

Someone at work is having this problem, i told them what i suspected but im not that familiar enough with how those op-amps work to know if its true, and i havent heard back from them about checking the +100v power supply.

The +100V is at 0 directly to ground (over the cap), so yes, the +100 is totally missing.

The range is now -90 to 0 instead of -80 to 80.

Easy to test, apply -10V on input, if it reads -90V on the output (or just measure the top input before ground)

PS. That’s from memory from my university time, which is a LONG time ago…


Thanks, hopefully they will get back to me soon verifying that the +100v is missing. Most likely because the associated power supply crapped out.

Everything you said points in that direction, since the 100V pull-up is completely missing from the equation, and the results you’re seeing perfectly match that.

After my decades of electrical work now discontinued bc I hate working for sloppy companies… I am inclined to agree with Splutty from that little pic provided. +100v missing either due to a bad connection, wire damage or bad power supply. I assume they’ve tested the wiring by now which should’ve led closer to this. If not… def do a continuity test. GL

Final heard back from them, and it was a loss of the +100v due to fault PS.

I’m totally unsurprised :smiley: