I've got a 2400c spec'd very similarly to yours. My NUpwr is the 240MHz variety.
Anywho, I couldn't say anything for sure about the first issue. It could be that something's aging and warning of failure in the future, probably on the power/I/O board. None of mine have ever exhibited that particular display anomaly, though I have had to replace that power board on one of them. The GLoD is typically a more common mode of failure for that component, though.
On the second, the G3 upgrades were often accused of running hot. This was often times true, particularly with the Newer upgrades. One thing you could do is disassemble it (there's really no other way to get to the processor card) and check that the processor's thermal pad is intact and making contact with the little 1" square chunk of metal in the bottom of the case that acts as the heatsink. When I installed the G3 upgrade in mine, I slightly bent the heatsink upward (it's attached only by its heat pipe thing, so it's pretty easy to move) to ensure full contact between the processor and heatsink. Aside from a few random crashes in OS X 10.2, I haven't had any lockup problems with mine, though it's still much warmer than the stock 603ev.
The Interware upgrades were much more desirable due to their lower temperatures and higher frequencies compared to the Newer cards, but they're much rarer in consequence.
Anywho, I couldn't say anything for sure about the first issue. It could be that something's aging and warning of failure in the future, probably on the power/I/O board. None of mine have ever exhibited that particular display anomaly, though I have had to replace that power board on one of them. The GLoD is typically a more common mode of failure for that component, though.
On the second, the G3 upgrades were often accused of running hot. This was often times true, particularly with the Newer upgrades. One thing you could do is disassemble it (there's really no other way to get to the processor card) and check that the processor's thermal pad is intact and making contact with the little 1" square chunk of metal in the bottom of the case that acts as the heatsink. When I installed the G3 upgrade in mine, I slightly bent the heatsink upward (it's attached only by its heat pipe thing, so it's pretty easy to move) to ensure full contact between the processor and heatsink. Aside from a few random crashes in OS X 10.2, I haven't had any lockup problems with mine, though it's still much warmer than the stock 603ev.
The Interware upgrades were much more desirable due to their lower temperatures and higher frequencies compared to the Newer cards, but they're much rarer in consequence.