Almost! +5V to EA will simply disable the internal ROM, it won't put the chip into programming/verify mode. For that you'll need to supply EA with anything from +7V to +23V, depending on the part. Word is +23V is for EPROM parts, +7V to +10V for mask (which these are).
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The NEC 8041 datasheet also doesn't give instructions on how to program the part or verify the programmed ROM, unless I'm mistaken. So I would understand it saying 5V to be "nominal" as saying that under normal operation, EA should only be at +5V.
I linked you to a script for dumping 8041 chips previously via e-mail; are you following the exact sequence as found in the script? Are you willing to share logic analyzer screenshots of the signals going into / coming out of the 8041 so that I can solicit input from other devs?
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Damn. I'll see what I can do to figure out what's wrong. In the meantime, the advice I have is to see about pushing EA beyond 7V, within reason, but be sure to have a current-limiting resistor to protect the chip; 7V might not be enough to put it into readout mode.
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It looks from the schematic that you have /RESET tied to +5V at all times. Meanwhile the instructions I have for the I8741 (a similar/equivalent chip) say to power it up with /RESET at 0V.
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