Hey Guys, I have a quick question for anyone. Currently I'm working on converting a discarded CD-ROM drive into an optical profilometer. I've built the necessary circuitry to amplify the signals and sum the quadrants of the photodiode but I can't find anything to help me identify the leads for the A,B,C, and D quadrants of the detector. is there any way anyone could point me to something that helps identify these? if necessary I can post a picture of the photodiode to help with identification. thanks!