Hp 750 desktop won't come on

2022 questions.
did it every work for you before now? and did PC move to different rooms or home?

is this a desktop???????? you said MON so is.
as old as 2018? this?????????????
HP ENVY Desktop , 750
HP ENVY Desktop - 750-170se CTO?????? true name found.
unplug both PC and mon from wall AC power for 15 mins
walk the dog
come back, and turn on PC first then monitor last
the PC fans must spin and blow air. CPU and PSU both.
the PC power lamp glows as the manual on PC tells. solid color.
PC video cable connected to MON,
if PC has video card, only those jacks work now.
turn on MON, next. (AC BACK)
if PC is dead (video) the MON will error out as NO SIGNAL
no connection (THEN GOES TO SLEEP)
no monitor model told or what cable used.
VGA, DVI, HDMI or DP./??????
this PC is sold in vast sub models no told by you
see that 750-170 above the 170 is the sub model codes vast.
they are not all the same and I can not see the rear of PC nor
MON jacks
but in the MONITOR, PUSH MENU KEY, THERE FOR OSD
AND TELL THE MONITOR WHAT VIDEO JACK OF 4 YOU HAVE CONNECTED TO THE PC.
ALL connections and all sounds and LED states matter.
and screen errors. and all blink codes of LED matter
and fans blow. all that matters.

read the code the blink codes tell the story,
red lights where,
1: power button LED green? (can be red) and beeps
2: Monitor LED lamps?
3: caps lock on keyboard blink.
4: is the COIN cell dead? 2.9v to 3.3vdc good, lower volts is bad , as most are this old !!!

http://www.pcdied.com/intel-magic/xw4600.html



the service manual covers all this! ever heard of HP and there REAL pages,,???
why not read that?
(do the fans all spin, if not PSU is dead.
PSU fan is first. does it.
CPU fan , huge fan on heatsink must spin.
the stock GPU card has no fan (ASUSc card but mine does. at ATI card.as fan right on the express 16 card.
does the DVD drive eject work.
if any of the above fail the PSU is bad.
but we strip off all loads from the MOBO
to prove its not some part shorted. first.
http://www.pcdied.com/intel-magic/xw4600.html

the front LED on this PC has flash codes
mine flashes in sleep mode, or w10 power off.
w10 never turns power fully off, it uses hibernate to turn off, (unless i cure that, ask)
the factory manual starting on page 111 cover this.
fully.

i own this beast so .....
code 2 red is overheated.clean the PC and all fans.
code 3 red, processor errors CPU.
code 4 PSU dead or shorts on load buses of same.
we call them power rails, we bench test the PSU
or read page 111 , how.
code 5 = GPU RAM failure, this PC has on board, GPU chip only X16 slot card, replace it. or the DDR2 rams are bad.
code 6 = GPU card bad.
code 7= BIOS ROM, put in a new coin cell first.!!!
Code 8= BIOS, always do nee COIN cell first.
code 9 = cant boot hdd, hdd bad or software gone, or corrputed, PC can now boot to a linux live CD or USB stick proving now PC is ok,
only hdd and OS suspected now. code 9
coin.
http://www.pcdied.com/intel-magic/slots.jpg

page 111 is here, 24/7 !

http://h50146.www5.hp.com/lib/doc/manual/workstation/hp_workstation/WS_UG_xw4600_STRG_453080-001_screen.pdf



http://h50146.www5.hp.com/lib/doc/manual/workstation/hp_workstation/WS_UG_xw4600_STRG_453080-001_screen.pdf

See


http://h50146.www5.hp.com/lib/doc/manual/workstation/xw6400/364898-001.pdf



Page 110 - M/B or Processor fail.

There could be many reasons for this. Open the case and make sure the components are plugged in tightly. Make sure the CPU Fan is spinning and is dust free.Reseat the RAM modules, make sure to clean the RAM slots before reseating the modules. If all this fails to give results, but a new power supply and try that, you do not have to install the power supply but can keep it outside and test it. If the MB is gone, then, look to see if she still has warranty, if not ebay may be a cheap answer for the same MB.

Go into My Computer and right click your DVD writer/CD Drive and click eject.

Any brand-new CD/DVD reader/writer with LightScribe *WILL* be compatible with your HP.
Check whether your "power" and "data" cables are the "old" style (white power connector and a 80-pin ribbon-cable) or the "new" style (thin SATA cables), before you buy a writer with the "wrong" (PATA versus SATA) interface.

power supply

Step 1 : Turn off the system by pressing the power button for 5 - 10 sec until the power LED is off. Removed all cables including the power cable (Exclude monitor cable and KeyBoard/Mouse).

Step 2 : Press power button for 5-10 sec again to drain fela power.

Step 3 : Reconnect the power cable at the back of the tower/computer and power on the system.

**If the same problem exists, Call HP tech Support (800-474-6836) because there is a high possibility that you have a bad Motherboard or Power Supply on the system.

Check if you have both cables attached to the CD/DVD drive. There are usually 2 that needs to be connected: the SATA or IDE (that ribbon-like connector that goes right to the motherboard), and the power supply (a connector that has 4 colored lines going to the power box). Make sure they are snug, and if necessary, try changing them with others that are known to work (there should be lots of spares). If the CD/DVD light blinks or powers on upon boot, it means power line is OK, but data cable connection is bad.

check if power jack working right. Try to change it with other jack. Sometimes the pins inside jack are loose. try to tight them.