This PAGE COVERS COMPUTERS CALLED by some... HOG POWER HP =  HOG POWER,   (as seen in the wild and no documents on the queer grade PSU exists!)
A.K.A, QP Queer power. (in fact the pins are not even NAMED !) <<  boy tech.s just hate that....
Many top sold OEM makers of PC have this nasty problem.  (not using  a real  ATX12V v2.31(+) standard spec, for PSU power supplies)     See here for my HP bench test.
The best cure of all is do not buy OEM PCs, if upgrades are needed now or in the future, or buy a real gaming grad PCs that can be upgraded, but do know that many can not or are very very hard to do so.

OR my real  true DIY PCs (as in YOU DIY !)   

The first things you see any  Queer PCs is wrong sized, PSU then see wrong cables and plugs and missing cables on the PSU, no 24pin power connector there. (oops it is Queer)

All of this information is as deep dark secret, and was discovered the long hard way. (meters used and tracing paths with great care)  by many folks, and the below is  a condensation of all work found in the WWW.
The OEM moved all power rail VRM's the Mobo (motherboard) and the PSU is  +12vdc PSU only (and STBY and -12v)
If you know ATX rules the below is a jarring shock. Even Alien sized cases ! I only cover real tower sized desktops, never will I touch any  SSF (small form factor).
HP seems ? to shun  real ATX spec. PSU , why they do we can only speculate.  ( I vote #2 and 3)  HP does not even document pin names nor even cover PSU replacement in the service guide, it is like it does not even exist.
Discounting the HP queer 12vdc standby power pin, this PSU is simple Single RAIL 12vdc Supply. (the VRM's of ATX were kicked out)  "voltage Regulator Modules"
My wild list of Why OEM's did this dirty trick: ( as most gamers scream!) a list of pure  speculation and facts. (more simple now)
  • To make  a cheaper PSU to save costs. (or to save space in a odd sized PC case)
  • To move regulators (VRM) to the mobo to make them work better (true) less noise and better regulation.(fact)
  • To add fan controls (true) (variable too)
  • Not allowing ATX power supples means , warranty failures can not happen doing this trick (speculation)
  • Save lots of cash on un-need copper wire.  (and moving the SATA power cables to the MOBO for 5vdc needed from there) fact.



That 7 pin SIP has "power-on" pin and "power- ok" pins. (if that is not connected the PSU/PC IS DEAD)    .
missing most ATX cables see? and orange arrow does show 12vdc amps and watts.
The sizes is 150mm long, but the width and height is dead wrong, 95mm and 73mm.
Yes yellow wires are mostly +12vdc rails, and black mostly is ground, but look at that 7pin bugger ?


The 6 or 7 PIN HORROR : (this Single Inline PLUG) There is no way I can guess why this keeps changing pin counts, it is so odd this. (but no pin names told by HP , but most are known by hackers)
Commonly see in HP EliteDesk 800 G1, Tower case, and mobo. Gen4 Intel CPU--i7-4770, +Q45 runs W10. Circa Jan 2004 made, with enimic 180watt PSU.
I call P2 the SIP, single inline Plug and it comes in 4 to 6 pins wired or 7pin with 5 wired. (varies by model and year PC)
We decoded this mess, including the magic fan pins 1 &2
(2x white is fan cmd and fan RPM) Green is PS_ON, Gray PS_OK for most. 6 or less pins. Empty pin is ground and may have extra black wire there. some versions of this 6 pin has no black ground wire at all.
Some times P2-1 is white-red  and not  solid white to make this more fun? If the 2 pins white are not wired then it has no fan controls and no need to jumper pins 1 to 2. (HP 590 has that) 
The 400/500 watt has a new pin  3 is ground and all pins shift to higher end .... The mother board  silkscreen paint  is  labeled  "PWR-CMD-P2."
Photo #1
is Elitedesk 800G1   , this sequence of photos shows the changes, in time. Up to Gen 6 (2020)   G2 started using 5/6 below. G4 up has 6/7 P2. pin 6 empty.


Z240 4over6 SIP(red white green gray)


HP

#702307-002 , 240watt PSU.

Purple is ATX +5vdcSTBY PSU to MOBO, but on HP it is +12vdcSTBY non standard and Alien to ATX spec. and is why you see eBay adapters using DC to DC converter there, 5 to 12v inline wire blisters.
To brench test this PSU , jumper P2 pins 1 and do and then jumper P2 pins 3 to 6 and this turns on the PSU to check voltages with volt meter or do load testing)
The Big red X below is jumper to make MOBO think fan in PC is under its control, but is not, on any ATX PSU used.
Here is the secret page.
secret 1 (don't tell)


The secret cure is here. HP 800 G2 example ( As seem on ebay and Amazon)  As you can see the top connector below is FEMALE socket (special Molex) that fits REAL ATX PSA easy..
The next wild thing is standby power, is not 5v but is 12vdc. oops, and can be had by using wall wart with 12vdc rating, to P1 Pin 6.  If standby is dead so be the PC. (power button dead)
The P3 plug is normal power to CPU from PSU, ATX. The below maker used RED for Gray.
Sold on Ebay and Amazon,  vastly.   500watt PSU at least to get 12vdc amperage higher.

Oddly enough California goes to +12vdc only PSU in July 2021 "ATX12VO" 10pins. using new INTEL ATX spec.  to do that.  (minus -12vdc was  obsolete from 2013 on, listed as optional )
 -12vdc was last used back in the RS232 days. (a relic from 20 years ago)
Most ATX PSU sold  now are with -12vdc  and in 99% of all cases never used now. (why it remains now is a big wonder?)
The tests I do are these: (green jumper in place)
  1. Fan spins at 4800 RPM and 750RPM when commad that on Pin 1 (P2)
  2. PSU turns on  with green wire jumped to ground. fan must spin 4800rpm
  3. PSU voltages are all good. on all pins stated above P1 and P3. Seen next link for spec on this too.
  4. Ripple noise not out of spec.
  5. Load bank tests, using huge load resistors seen below. to the +12vdc pins.



DATA amd FACTS here ,even and optical tachometer tool (laser) and  scope views.
The above PSU, from HP is bench tested like this: 
There is no PC  or  mobo (motherboard) connected at all , just 1 PSU on the bench. HP-p/n 702309-002
Just like a real PSU we jumper the P2 green to black (ground) this is PWR_on to ground jumper  Pin 3  green to any black wired pin) with paper clip unbent. (SOP)
The PSU then turns on (AC line power connected) for sure , if not the PSU is dead. The fan spins fast (inside PSU) now.
I then test all pins of all jacks for proper voltage with a voltmeter (DDM set to volts) black lead to black wired pins any.
P3- pin 3/4 are both +12vdc (other 2 are ground black) All green voltages are real test results.
P2 pin 4 is power good pin GRAY,  high = OK = +3.25vdc  , Low = 0v is fail, means PSU sees bad output or one or more outputs are overload or dead. (in this case 0v means PSU IS BAD)
P1 pin 3 BLUE , is -12vdc, (it is not needed, on  most PC's made, but my guess if  it fails the PSU thinks it is defective (I get this =   - 12.6 vdc)
P1 pin 4,5,6 Yellow, all 3 are + 12vdcP3-pins 3/4 are brown at +12vdc
Pin 6 Violet is standby power and must be  +12vdc  present with jumper above not connected and after.
P2-pin1 and P2-pin2 check out as follows:  pin 1 is fan command.  and  pin2, is tachometer  pin, output.
Forcing pin 1 below 2.0v (with a pot to 12vdc) The fan goes to slow speed, there is only 2 speeds (this crude wah), fast and slow, slow 0v, fast over 2vdc.
But...
The tacho pin is pin2 is an  open collector driver transitor inside and needs a resistor (called a PULL UP) to 12vdc, and low speed is PRT = 40mS and fast  is 6mS periods (square wave.) The actual fan inside has 4 wires)
The tool called optical tachometer shows 4800RPM on fast speed.(LCD) (a ratio of slow to high is 6.6:1) so low speed is 800 RPM  and super quiet then.
The internal PSU tach is 2 pulses per turn. (now we know that fact) and is known to be common in this fan industry world. (PCs)

So at low speed,  scope shows 40Ms period  is 25hz or 25 clicks per second 2  clicks per second mean 12.5 turns per second then  math 1 time more.. times 60 is 750 RPM.  (bingo math matches the tool)

Ohm-meter checks show Pin1 reads 16k ohms to ground, but pin 2 tacho pin reads infinity ohms.  (pin 1 is output and pin 2 is an  input) 2 more facts.
The FAN command pin 1 out of the HP motherboard (600 G1?) I do not own, may (I think so) modulate  pin 1 for any speed from  low to high 720 RPM, using good ole' PWM modulation common in the industry)
All secrets worth knowning solved.
Now the last tests are load bank testing, and last ripple. (PSU have a chopper inside that love to make noise if the CAPS are bad) 40,000 Hz noise and very very bad for all PC electronics.

Load teasting is next.
I also do load testing using a pro  grade load bank or make my own.
A good test is at last 6 amps  of load.
R= E  divided by I , so 12 divided by 6 is 2 ohms.  Best is 2 ohms is more easy to find and is  72watts of heat to burn, so I use a 100watt 2 ohm test power resistor. (P = I x R)
As seen here.
Do not hot plug connect the Resistor, do so power off, then connect the test resistor and then turn on the PSU.
This works on all +12vdc pins but not on -12v or +12stand by pin.
The Standby can be tested at 1 full amp. and a 12 ohm load  of 15watt resistor rating , is also wise to do (test).
 
Load banks are the best test of all.
I have scope too and check for ripple using the ATX spec, go BACK, one page  from here. (hit home above and find RIPPLE)
end testing. (my load is here)  2 ohms  cause 6 amps to flow on 12vdc pins, and gets hot, with  (P = I x R) power of 72 watts. DC power. (or P = I  x E) 6 x 12 is 72. This resistor cost me $10, and have others here.



Examples of real queer PSU by HP and the real world of ATX.  ( as you can see a real PSU will not even fit at all)






DIY PC's are 10x better than any OEM, buy the case you want first then mobo and load up the PC with all standard parts. (end the misery of OEM PCs and endless bloat-ware)
I picked  huge case with large slow quiet fans,  1 fan in  front and 1  rear too, for super cooled PC that lasts far longer than hot running PCs. Go hog wild spend $100 on a case. (endless choices today)!!!  See mine here.
A top quality case has a top, rear ,f ront and bottomv ents. (no change ever again to overheat)  all 4 of the 6 sides are vented with screens. (<< yah !)
Buy the great Asus, Z270prime or Z370 on up. (or from Gigabyte)  The mobo lets you control fans easy in its great BIOS. "fan curves too !"
Any DDR4 that you want.  16GB is plenty.
I7 quad core+ . (use Asus DDR and CPU QVL , qualified venders list , omg simple and bliss that) Buy any CPU you want via QVL list.
and 1TB SSD drive, m.2 or SATA SSD.
PSU, pick the modern new single rail PSU, 500watt to 700w. semi modular  or modular.  Example 1:
Now you can get help easy and upgrade at any time, with no restrictions.
Last and best any GPU you want will run here,  GTX-7xx up for w10-64bit. A GTX1650 is plenty good. (I can run 50 top games fast, even Metro Exodus.)
If you do this, you now have full documentation on YOUR BUILD,unlike any OEM maker of any PC. (No more having to do the above cable trick to upgrade any PC you made !)
None of this is hard at all.


Found on the web (www) GOOGLING.
OTHER HP PC's
(the Mini's) Class  PC: (much more easy to cure) (also the HP mini keyboard is hated due to backards Fn+F1 up keys, cure is real keyboard generic)
Some only are with 24pin micro molex alien jack and do not fit normal mini molex (ATX spec) easy fix. (yes HP used the smaller size 24pin jack to have more space on more tiny MoBo.
All easy fixes are on Ebay or Amazon, under title HP, Power adapter 24pins.
Plus all these: as seen on Ebay, many:
24 Pin To 6P Converter Adapter Power Cable For HP Elite 8100 8200 8300 800 600G1 (5vstby to 12vstby) and 800 G1

ATX Main 24-Pin to 6-Pin PSU Power Adapter Cable 18AWG for HP Z220/Z230

ATX PSU 24Pin + Dual Molex IDE 4Pin to 18+10pin Power Adapter Cable for HP Z800

ATX Computer Power Cable 24 Pin To 18 Pin Replacement Adapter for HP Z620/Z420\\

ATX PSU 24Pin 18Pin + Dual Molex IDE to 6pin for HP Z600 Power Supply Cable ( but but no PSU fits here not sure me why this  exists but does on fleabay.)


Slim line molex micro to mini  adapter cures the wrong connector conundrum.
Compatibility: HP/Compaq; Mini ITX motherboards
Condition: New
 

    Adapts between ATX Mini 24-pin and 24-pin PSU connectors

    s3500f, s5160f, s3521, s3100n, s3521.uk, s3500f
    s3521.sc, s3521, s3122x, s3521.uk, EN996AA, s3521.sc
    s7310n, s3122x, s3120n, s7310n, s7220n
    s7120n, s3120n, s7210n, s7120n, s7400n
    s7410n, s7415c, s3431, s7420n, s7210n, s7421c, s3431.uk
    s7500e, s3430f, s7500n, s7400n, s7500y, s7410n
    s7510n, s7415c, s7515x, s7420n, s7517c, s7421c
    s7527c, s7500e, s7530n, s7500n, s7600n, s7500y, s7603w, s7510n
    s7605n, s7515x, s7612n, s7517c, s7613w, s7527c, s7617c, s7530n
    HP 5188-7520, EN996AA
    HP 5188-7520
    HP 5188-2755, s7220n
    Slimline s3431
    HP 5188-2755
    HP 5188-7602
    s7600n, s7620n, s7603w, s7627c, s7605n, s7320n, s7612n, S3400T
    s7613w, s7700n, s7617c, s3707c
    HP 5188-7602
    s7712n, s7620n, s7713w, s7627c
    s7727c, s7320n, s3220n, S3400T
    S3420F, s7700n, s3707c
    s7712n, s7713w, s7727c, s5120f, s3220n, S3420F


spec
wide
tall
long
ATX
138mm
64mm
150+mm
HP
95mm
73mm
150mm
As you can see it is not ATX at all.
SFX PSU is way too tall at 125mm (scratch that)
A Closer match is A FlexATX form factor PSU, 1999 now mostly gone (40.5x81.5x150, is too tall) falsely called a  micro ATX. (there is no such PSU) or falsely called Mini-ITX.
There are 2 kinds of PSU , OEM junk (Proprietary) like see, inside HP or Dells or industry spec PSU, ATX is best. Look here and see left  side of page for a real PSU.
Mini-ITX is 81.55mm(tall) x 40.5mm x 220mm if not too  long can be using winged brackets (left/right sides) you make by hand to bolt it in. THIS CAN WORK. if not too long.  or this.
If that makes no sense (brackets)  as any skilled TIN bender this or don't buy HP.
220mm = 8.7"inches long. many A PC this hits card cages inside, so remove them and go side clamped SSD. Hits DVD cage? go DVD free remove it.

Normal size  in Grengo imperial inches is ATX , 5.4" W x 2.5" tall, and 5.9" inches long or longer over 700watts

There are other standards and those too are mostly ignored by OEMs (not sure why, only is, except some top gaming grade PC's tower desktops)

Not easy to find, at all but my 2 links above find some.


version 4.  12-1-2020  (  this are the tests I did to learn what is inside and what it can do even the fan secrets told)  this is mirror site page found, no idea source.