Just a quick one, what motherboard revision do you have?
The 1D4 and 2B motherboards have problems with Apollo cards. You may need to do the timing mods (which I can't find at the moment).
I have an Apollo 1240/25 and it exhibited similar problems to your machine until I did the timing mods.
For power supply info, read this guide I wrote on Aminet
psu-problems.txt hard/misc 6K 1 Diagnosing power supply problems
Bye,
Ian
