If you're in doubt you can take all the RAM off the GG, but I doubt that would cause a guru.
Clean the connectors if you want, then boot with no startup-sequence. After that run Setpatch as you're using an 040, and run the digger manually. The files you need to run are called "digger" and stuff - you'll find them in the GG directory.
Also try removing the 040 so you're back with the 030, and boot off the GoldenGate disk itself.
If the GG itself isn't running you'll get an error like "Cannot coldboot GoldenGate: no bus activity" usually, so it sounds like the error is on the Amiga side.