Constant PCA failing / reset - PC build issue?

[Gumby]

OK, I should have been more precise, I meant the RS-232 return.

I have seen weird effects when the return path was established via the power supplies and mains earth.

[jpdw]

Remember this? Solved!

Thought I'd complete this thread in case anyone stumbles over it in the future.

I didn't get any further with this over the winter months. Partly due to lack of time (baby twins) & partly because turning off the server running the heating would not have been a popular move :-) . It was always my intention to re-house the server at some point anywhere.

So, this I have now done, with one of the Mini-box M200s from Linitx.com. But I also got a new PSU - one of the PicoPSU jobbies (this one). Anyway, the built-in serial now seems to work. Which means it was most probably the DC-DC PSU board I was using before.

Although the old PSU was a 60w unit (and I'm just running the mobo + 2.5 in HD) I either it couldn't supply enough grunt to one of the individual power rails or the grounding or voltage smooting wasn't enough. There's a small chance its chassis grounding but I think more likely the PSU.

Overall this box (winxp, cortex, via en1200 & 2.5in HD) seems to be pulling about 17-19w off the mains, peaking around 22w... That's 2/3 of the 30w it was running at with the big ATX PSU during the whole of last winter.
And I've got a spare small PSU to pair with my spare CN1200 for another "project" :-)