It's the one below the one I posted, though it doesn't have the exact model as the one in the auction.
http://www.nidecpg.com/fanpdfs/c2003_4747.pdfYou don't happen to have a laser tachometer you could use to measure the RPM, do you?
I actually looked at that but, as you correctly point out, since it did not have the exact model number, I discounted it .... seems correct though.
..... laser tachometer ... I hate giving negative answers, but, no I don't have one. On a positive note though, yes you are right by implication that I do not get any RPM readings on either of the rigs I run the TA500DC fans on (could not get one connecting the orange or other wire ... must be something I did wrong!)