I got the picoscope and measured the reset and one of the clock lines. Red one is the clock, 4MHz as expected, blue is the reset line, and there is a sawtooth signal. According to the schematic, the IC controlling the reset line should be a ICL8111 (Site 108, U144 in the manual), but the part number on the IC that is actually soldered onto the PCB is ITS6728. I measured the resistors R162 - R164, and got R162 = 15.02k, R163 = 1.000 M, R164 = 15.06k, which is way off, but I am not sure if I can trust the measured values without having to desolder the resistors. Also, R163 looks suspicious, and maybe the last owner replaced it or something (see photo). I also did a diode test on the CR111 and CR112, both have about 0.59V in one direction and 2.85V in the other. R107E reads 2.75k, but, again, not sure if something else in the circuit is affecting the measurement.
Any ideas?