Hm, probably following the same principles used by other cart consoles. But first you would have to find out a) pinouts b) timings Im sure there are dumpers out there..Its an old system! EDIT : http://thedump.classicgaming.gamespy.com/neogeo/ perhaps the guys over here can help.
Unlike most systems the easiest way by far is to dump the ROMs manually, especially if it's a socketed proto. I've never heard of a Neo proto not on a MVS or on the dual AES/MVS test board, so you shouldn't have to worry about access to the ROMs/ruining the case. It *is* possible to make a PC controlled "external" ROM dumper, but it wouldn't be for the hobbyist faint of heart. There are no commercial Neo dumpers out there. I think The Dump's ROMs all came from contributors, and most of the time were just ripped from old scene floppies. The original Neo dumps came from old MGD2 sets, which were dumped by Bung from AES carts likely using a hand-made PC based dumper or MGD2 attachment for early carts. The Dump's MVS redumps were manually read using a device programmer. A DIY parallel port or microcontroller dumper would take between 10 and 15 off the shelf chips and up to 300 wires... Since the Neo's CPU can't access audio, character or Z80 data (like most arcade systems), there's no way to exploit the hardware itself for dumping either.
It's a very easy system to play around with, but Neo CD is even cooler because it practically has a built in dev unit; All you'd need is a PC<->NEO cable and custom loader to upload your game data to the different emulation RAMs.
If the drive is dead, a loader could be hacked into the BIOS. A PC<->NEO cable has been developed by Razoola for his "Universe BIOS", see here: http://unibios.free.fr/pc2neo.html it/something similar should also work on the Neo CD. I think the coolest thing about Neo CD is that if your game fits within the Neo CD's memory requirements, you can just load the entire game once through the IPL and not write any CD specific code!
