I had to open my MX to calibrate the focusing screen. After assembing it back only the bottom diode of the light meter is lighting and there is not any response to light, I turned the asa variable resistor under the speed/asa selector 360 degrees at no avail - simply quited working.. Any ideas?
Maybe the Photocells are dirty and/or are being blocked by something. They are located in the veiwfinder housing, one on each side of the finder.That would be the first place I would look. Good Luck