Cosmic Chasm has a lot of engineering hacks. See the manual on spies; I believe they are included. Also, check the Star*Tech journal for other fixes on this game.
David Fish came up with a great hack for those of you who have a Cosmic Chasm board, but cannot find the original G08-105 or WG6400 monitor to play Cosmic Chasm on. Here is the modification. Though it is not perfect, I was more than pleased with the results.
The original encoder from Cosmic Chasm is PC66D-256-5. Viper and Danger Zone, two other games from Cinematronics, use the PC62D-256-5 encoders (two apiece). These work as great replacements.
Monitor used: G05-105/CC0
Tube: 19VNJP22
Standard Sega XY G08 transformer should be used.
Fix: On the PROM board insert a jumper from pin 6 (G1 input) of
U19 (74LS138) to +5VDC.