The Sipex DAC9377-16-4 has a strange aging problem: resistors in the ladder will drift in value until the analog output is not only non-linear, but en tirely crazy.
:)
DAC 9377 is common in hospital NMR, military simulators, and older custom r esearch instruments. (If it ran any proportional hydraulics in manned simu lators, they'd be in for an increasingly rough ride over the years.) The o ld chips are expensive if you can find them at all, and of course may suffe r the same aging problem.
So, build yourself an adapter-board to match Texas Inst DAC712 pinout. See link below. Needs one signal inverted, pullup/gnd of mode pins, and zero/ gain trimmers on board. See: