I never had any issue with my M-Tec 030@42Mhz on my A600.
It has the necessary fans to be sure that heat doesn't affect the CPU and everything works as intended.
Mobo revision it's not an issue (at least known) as it is with the Apollo 630. My mobo though it's an rev1.5
Try and clean the metal surface of the 68k along with the M-Tec's female socket metal surfaces (in case they don't make a nice and firm connection).
PSU is not an issue since I'm using an A500 brick also and I never had a problem while having HD, CF Adapter and 2xFans internal.
My version is the 4MB which is PCMCIA friendly.
It's weird though... these exact symptoms I'm having in my A1200T with my Apollo 060 - although these must me timing issues with the mobo... Anyway...
I hope you'll manage to fix it cause the M-Tec is a very stable and reliable piece of hardware for the A600.
