Kenjr posted:… I powered some incandescent lights and with the voltage at 13V, the lights did not flicker (volt display was stable; amp display varied from 0.4 to 3.0).
0.4 to 3.0 is quite a fluctuation. I'd think you can meter the inputs to the box marked "A/D". The text suggests this will be a voltage proportional to current and probably 0-5V DC range. I'd think you want to see this test point fluctuating wildly so you can trace backwards thru low-cost generic components to the current-sense resistor.
OTOH if the inputs to the "A/D" are nice smooth stable voltage proportional to current then I'd be nervous. That would suggest the problem is downstream toward the microprocessor - such as in the analog multiplexing circuit which (given the technology of the time) was probably used to share a single A/D converter amongst the (at least) 4 inputs (2 V, 2 I). Then you'd need an oscilloscope to see what's going on.
