Cappy, *maybe* your grounding situation could be the culprit, though since I lack any knowledge regarding Cary's circuits, it might be worth a quick phone call to them for verification.
The only other thing I can think of is that your power cord might be wired backwards (if removable). I assume you've tried swapping it out with one or two other replacements as wiring mistakes do happen whether hi-end or cheap molded variants. Lots of equipment can still operate if reversed, but some circuit designs may take issue.
Also, since you haven't confirmed my question pertaining to your Cary being powered up with *no* input or speakers cables attached, have you tried powering it up with *only* speakers connected (no inputs)? Have you tried swapping speakers and speaker cables - independantly - just for troubleshooting sake (even using cheap speakers and lamp cord)? Note: The amp may not operate without speakers connected, and may trip off as well. See the operation manual for any warnings regarding operation without speakers connected.
Final advice; Be as systematic as possible while troubleshooting, change only one item at a time, and don't *assume* anything. After that, if you're *absolutely* sure every thing's wired correctly (including your AC), and Cary states your grounding configuration doesn't pose an issue, maybe someone else may have additional experience regarding acceptable DC percentages, if present.
In touch,