measure pwr ouputs from internal (?) faulty pwr supply or MBoard for HP desktop PC.

[keyboardjock]

tech problem!  does anyone know how to check the power outputs from (old PC) internal  HP pwr supply ( part 50376-001, spare No: 508152-001 that fits a desktop pc.

most likely discontinued line.  I am refurbishing.  pwr supply not coming on - may be main board itself?  ( +/- 12V DC output, various Watts ) 

cable bundle plugs into P1(6pin) P2 (5pin), P3 ( 4pin) on M/Board. I believe there is a cmd switch (?on p2 ) that tells pwr unit to activate as a feedback from MBoard since pwr supply wont start up unless all plugged into MBoard..  I have a generic pwr supply tester , unfortunately config of pins on tester doesn't match the 5 pin P2 plug! the rest of plugs go ok. therefore cant test pwr supply box output.

pwr supply fan doesn't activate on connection to mains.                       see pics att.

does anyone know how the cmd plug works? am thinking of making a male 4 it that will simulate feedback from MBoard, thus activating pwr supply, thus enabling a reading of  volts on tester or a multimeter. any other method welcome. thanks. 

MG

[Kumar0307]

@keyboardjock, Welcome to the HP Support Community!

• Which model HP desktop are you using?
• Refer to this document to know how to find the Product Name or Product Number.
• Do you see any lights on the tower or the power button?
• Do you hear any beep sounds?
• Try with a good known wall outlet.

Disconnect all non-essential devices such as printers, scanners, external hard drives, and similar devices. Remove or disconnect all discs and devices from the computer, except for the mouse, keyboard, and monitor.

Perform a hard reset on a computer:

1. Turn off the computer completely; disconnect the power cord from the back of the computer.

2. With the power off and the power cord disconnected, press the power button on the computer for 5 seconds. The power light indicator on or near the power button might turn on briefly but then go out.

3. Reconnect the power cord and turn on the power.

Note: HP recommends connecting the printer directly to a wall outlet rather than a surge protector or a power strip.

Let me know how this goes.

If you feel my post solved your issue, please click “Accept as Solution”, it will help others find the solution. Click the “Kudos/Thumbs Up" on the bottom right to say “Thanks” for helping!

[keyboardjock]

Thanks for ideas. PC is HP Compaq elite SFF   Ser: AUD14401MC. unit has Core i5 2400 M/Board main chip. I work for a licenced refurbisher in Perth, Australia and am trying to get 2 of these units going-similar fault - apparently no power to internals.  have checked incoming AC 240V and cables. No peripherals are att. have done a hard reset x 2. 

when turned on normally , small M/Board LED comes on, seems promising...no beeps. as mentioned no easy way to check internal power supply outputs correct V and amps using generic pwr checker. can try V-meter if I knew outputs from the leads. Looks like 1 lead is a control feedback as it plugs into cmdpwr  point on M/Board. I am assuming pwr supply senses M/Board ok, then activates pwr unit itself to come on.

tried back to basics: removed  pwr to  internals ( HDD,CD), removed RAM. turned on- got ram beep as expected. re-inserted ram, hdd and cdrom progressively.  didnt seem to make a difference.  tried ram in different slots, have checked ram against intel specs(ok). changed ram to another maker, tried singularly, paired etc and various positions- suddenly unit starts up!!

am running 2x 2G DDR 1066.  great..but cant reproduce result now!  ? something wrong with board bar that ram plugs into.  pain in the ….   any thoughts now? . still suspect a bad M/Board, but unlikely its both PC's, so therefore, still need to problem solve it.

qn: does pwr supply use cmdpwr plug via the p connector(s) as a activation switch?  how is this achieved so I can measure using a v-meter  on the female plug coming from pwr supply...  pic of internals att. the 3 plug in points on board indicated.

MG.

[keyboardjock · Accepted solution]

hi all, have solved problem. pwr supply apparently ok, moved RAM  DIMM position, all goes. also has lightly dodgy front on/off switch.

MG.