[G4] MDD sudden quits

[Jay E. Krauss, Jr.]

	I have two MDD G4s, both maxed out with 
four hard drives and 2 GB RAM and running OS X 
10.4.2. One gives me no problems; the other has 
developed the nasty habit of suddenly turning 
itself off. I've taken it to an Apple authorized 
service center once and a logic board was 
replaced. This solved the problem for about a 
month, now it is beginning to happen again. Tech 
Tool Pro detects no problems with any of its 
tests. The hard drives check out with both Disk 
Warrior and Disk Genius. I've hooked it to a UPS 
to eliminate possible electrical fluctuations. 
The CPU temperature stays under 59° C and the 
hard drive temperatures 37-44°C (similar to the 
functioning unit).
	Has anyone else run into this problem, 
and if so, was there a solution found?