A good reference on the startup resistors:
https://colintd.blogspot.com/2016/10/hacking-hp-common-slot-power-supplies.htmlI completely overlooked it initially as "geek speak", but the author colintd's clarification of the likely assignments or functions of pins 33, 36, 37 etc. was very enlightening!
He states essentially that pin 36("Present") is likely intended for the PSU to sense being "connected to the server" by a 'voltage pull up' when inserted into a server's slot. This 'pull up' of its voltage can be mimicked by connection with pin 37's "Standby 12V" or pin 33's "Enable" voltage ("pulled up to the PSU internal 3V3 bus via a 10K resistor").
But what is really revealing is that he goes onto suggest that the voltages, resulting from the range of usable resistors, between pin33 and pin36 are "unconventional." Apparently the "splitting of 33 & 36, into a pulled up / clamped "present"(36) signal, and a simple pull to ground "enable#"(33) signal (which can also be driven over I2C) is much more consistent with other PSU" he has worked with. Further, "a fixed 22K resistor from "Present"(36) to 12VSB(37), and a separate switch between Gnd and Enable#(33), ... leaves the possibility of software control over the PMBus(Power Management Bus)." In other words, one can do more with "conventional"(as intended) connections(than the method of connecting pins 33 and 36 which 'does the trick' but limits other control features, that would otherwise be available).
Pin 34 is apparently a "Current Monitor" output (60mV/A) so it's got a current meter built-in and a "6:1 resistive(voltage) divider to ground would give 10mV/A, and you could then connect a cheap 0-1V voltmeter module, ideally with programmable decimal place, to directly display current in A" which means adding a bulky current shunt or even an inline Allegro current sensor IC is not even necessary! Dang!
![Clapping :clap:](https://www.eevblog.com/forum/Smileys/default/clap.gif.pagespeed.ce.LImJbaO0yv.gif)
This should apply to many similar model HP Common Slot Power Supplies so this is very useful info!