E3400, but now it's with an older 430, to rule that out (could that have been an issue anyway?)
The fan spins, kb leds flash, mobo components get a bit warm, all in all normal... except no go
PSU voltages seem fine, 'power good' changes as it should, CPU and mem voltages are there (some 1.4 and 1.9V).
Tried also with an old PCI video card, besides analog IGP output. System responded to a CMOS reset, as now the power off delay is gone. Seems to feel the reset signal too (slight change of speaker noise).
FWIW sellers attested mobo and memory worked before shipping (separate sells though).