Power Up Basics (Neo Geo CDZ)

the neo geo cdz has a 10v and 5v dc input both rails ideally need to be able to supply 1amp minimum the 5v rail actually wants to be 5 2v approximately for stable boot when booting from bench at 5v it never works, increasing to 5 2v makes it work if you want to power from the bench, apply 5v and 10v to the pnp transistor emitters nothing will happen until you press the power button which will then enable the base of each transistor passing power through the 5v rail seems to pass exactly 5v through, so is likely there just as an over voltage control the 10v rail is regulated down to 7 5v the 5v rail pulls around 400 500ma when running the 10v rail pulls 140ma if no drive is connected, 250ma if one is connected, and 500 700ma when the drive is spinning minimum boot the system must have both of the 5 2v and 10v applied to boot the cd drive does not need to be connected however, the front controller board must be connected not just for the power switch (this just shorts the yellow wire to ground), but if the buf logic chips on the underside are not detected (or possibly the front board just shorts something to ground, i haven't reverse engineered it yet) you will get black screen when powering on you should see the cd in the center and the neo geo cd text intro swirling around the disc and then going along the bottom, followed by entering the cd player screen with various controls such as time, intro, program, play, stop, pause etc black screen / flickering sync this is common if your 5v rail is a little low even using a high quality bench power supply it seems the 5v input is expected to be at least 5 2v otherwise it doesn't boot if powering from bench, use 5 2v instead