Okay so my setup is the original 1988 white pc engine cd unit and IFU. After playing it a few times the cd drive randomly stopped spinning. I confirmed this by holding down the "lid closed" lever and trying to play an audio cd and the thing clearly wasn't even spinning. I finally got fed up enough the crack the thing open today. After opening the cd drive case at the bottom the first thing I'm presented with is this massive ground / rf shield plate. This plate is only separated from the solder side of the pcb by a very thing layer of plastic. The plate also goes up the sides and has no plastic in between. There's two big metal prongs that stick up from the plate and connect to some ground point on the pcb that happens to be right next to a bunch of pins for the drive connector to the ifu. I removed the plate, and the cd drive revived like new. Then I tried removing the cd drive from the ifu and it wouldn't come out until I lifted the whole thing out of the bottom half of the case. There's two ground nubs that stick out of the ifu and are supposed to connect to metal from the missing ground plate. Since I removed the ground plate the nubs went into a hole and got in the way of pulling the cd drive out. So I just cut a piece of plastic and glued it into the hole so I can remove the cd drive again. Here's a picture of the plate I'm talking about sitting next to the cd drive with a piece of plastic filling the nub hole:
And here's my revived pc engine cd setup with the plate in plain view so you can see it runs fine without the plate:
That's one stupid design flaw..