Optiplex 3020 power button not working.

I have same problem. My pc doesn't respond to the power button. No led glows and nothing happens, i tested power supply unit, and it is ok. Even voltages are ok on psu. I am Electronics engineer and know that issue may be in IC of motherboard. But without schematics its impossible to identify the damaged ic. If i got schematics of power button and its related  ic, then i can identify the problem and possibly solution 

3020 MT the big case or what?

nice hyjack.  why do that , post your own full and complete symptoms please,

the first part to check on 3020 is the RTC coin cell 2.9v to 3.3v and below is bad. bad for sure. or bios FAILS.

use DMM  meter, measure hit in seconds.  they fail in the 5-7 year bathtub, (EE knows that name)

the PC does lots of things, turned , on and sounds., LED glow many, and beeps. HDD pins sound.

are the fans dead.? (not stated) do this RESET?

Good an EE man, very good. there are no schematics, at all. ok>? its OEM non ATX, DELL proprietary.

but Intel bless them have full  schematics on there older PCs, (real) and a great great learning tool.

the PC needs to be hard reset, as an EE you knows that ESD causes latchup and some chip do that (USB as 1)

do so and stay that way on purpose. (input ESD protections) and CMOS latchup and PC stuck in sleep mode.

all three are RESET BY DOING MY (ALL PC Forums and sites state this) just 4 easy simple steps, for all PCs on earth not laptops,  and yours is not LT.

the goal is get the fans going at least CPU fan, must spin,. and yes power light glowing right color blue'-ish

the goal #2 (PC boot in a serial fashion)  is SCREEN working, see POST LOGO DELL this must happen.

The power button on all PCs goes to the intel, (if intel) South bridge, and the chip sends "power-on" line command to the PSU

the PSU sees that and must turn on for at least 1 second, (mine fail in 1 cycle of 60Hz line power, with my more fancy DPS PSU magic) beating out the 1 second ATX rule (but less is spec too) an important key fact in the ATX world this, it means the PSU might only run for 1 full second or less. (even 16mS on my PSU and eye blink fast that.)

the Mobo can also end the PSU power on state too,  the MOBO has VRM's.  that do that, sees any overload of any kind and tells the PSU to turn off in 1second or less.

so what your PC shows, is power failure,  hard.

1. do the long hard reset, first. (new version now)
2. if dead do the strip down, any thing connected to the PC can short and if they do the VRM /PSU shut down fast, even so fast the PC will not turn on at all, a fact. do the 14 steps there, find the short,  this magic prevents smoke and fire, you well know and understand as an EE.  (and NECA /UL rules etc)

Get the fans running first and not mentioned by you. (sure nothing means no fans got you I did)

the DVD must eject the tray with botton next to said tray.

the mobo glowing tells you standby power is ok..

the power button must be plugged in correctly at mobo jack.

the LED behind button (I own a 3020MT) must glow amber or blue/white) if not?  power on is failing for sure.

south bridge to PSU. 

the 4pin CPU power cable must be connected or the PC will dead,  both power cable from PSU to MOBO

are mandatory.

warning some PSU fail only with loads,  the jumper wire test is very good but loading the rails up matters more.

EE would know that  so sorry telling obvious.

the 3020 is one of my fav, PC, after my T3610, that is, and my z270 prime.

see my pSU wiring here.(custom PSU if you want to try that, it does work well)

Yes LATCHup can sure as shoot'n make the south bridge go dead, and is in fact a FEATURE.

not really dead, as in broken just fails to respond for self preservation, vast chips on the mobo do that.

most do. or all do. (study ESD protection in silicon, it is a big topic) and even stronger now. up to 26,000 volts protection in fact. ESD can go that high or for near by (not direct)lightening hits.

hi sir, thanks for your quick reply.  Cpu fan doesn't spin when i plug the supply to mains with mains on (as usual optiplex does when we switch the mains on) and no led lights. When i press the button on pc nothing happens.  No led no fan spins. But When i press psu test button located on psu, only cpu fan spins, but nothing happens. I manually shorted the button pins on mobo, but nothing happens, even no any sound from int spkr. 3020mt has big case

oops forgot the 10 second rule.

the south bridge chip , (does the ACPI sleep jive) and the 10  second intel rule inside that chip , ends sleep.

hold the button power for 11 seconds to evoke that rule. this is in silicon , dell has no control here.

if this fails , do my long hard reset (AC power gone and pulled) below BTN = button

did you push the power button in the PC for 11 or 12 second to evoke the 10 second intel rule.?????

y/n? yes and failed.

if yes do this next., step 1, to 4.

that step ends LATCH up   CMOS,  and 2 other modes of like kinds. (most chips made do that?)

if the button is still dead and PSU is good as you seen to imply

then next is the strip down testing, posted above.

you do kow that all VRMs in this PC , all PC shut down or stay dead, for 5 way protection right.?

all starting with the word over or under,   (even OPV , over power protections) for any shorts at ANY POINT;.

VRMs are voltage regulators,  and are fully protected from any illegal load events SHORTS.

the PSU has only 1 rail 12vDc not counting standby 12v

the other RAIL VRAMs are on the dell MOBO all are.  and if any card or device shorts the VRM shuts down

and the PC is now DEAD. BY DESIGN,  Dell is not ATX spec but in truth they only moved the VRM,.

works that same but is not ATX spec.(lay out)

even a shorted USB device can take you down. better PCs, just shut down the VBUS, for USB> not all are that good. some overload the PSU 5v rail.

learn that in the real would any thing can short.  learn it and expect it, and win. do that test, I called strip down.

sound complex and is at circuit level., but not really from the tech view.

in fact if I was in your room now

in 15min the PC tested for latchup (long hard reset, then stripped down in 15 min flat,

and testing ram 1 by 1. down to the classic Minimum system, USB pulled first so easy and fast that.

pull DP cable or HDMI, both have a power pin so off they come use VGA/DVI, no power pin there. or none.

side lid  off and pull all PCIe cards. still dead? add still dead to each line here.

pull all SATA cable 2 each drive.

pull all ram test 1 by 1, just like my 14 step page shows.  clearly.

even a fan can short , rare sure but why whole any tech no expect all things to  short, and prove otherwise.

strip it down then learn the truth. 

some PCs beep if all RAM is pulled , shows signs of life. but 1 stick is need top run firmware, a fact.

10 sec rule doesn't work.  I tried it.

 this is connections, how shoud i disable vbus On mobo?

Hello sir, i did hard reset, and striped down. No ram put in it, it doesnt sound. Nothing still and pc is dead. I pulled motherboard out. Only now motherboard , psu with 4pin cpu cable and 8pin pwr connector is connected to mobo, intruder  switch  cpu with fan, speaker , and pwr switch is connected to mobo. Nothing happens 

it needs 1 stick of ram or PC will be deed (it may beep no ram) but BIOS will dead and with that dead booting will be dead,

if the PC fan is good and power on shows no BIOS screens. the PSU is bad.

if all sticks of ram fail 1 at a time the PSU is bad or mobo bad or shorts on it or to it.

to fix any PC one needs spares, there is no way around that fact.

most shops have spare PSU, if not go broke fast for sure buying expensive MOBO.

but gee this PC has $13 mobo for sale on ebay. even free ship. amazing no the glut of used business PC guts.

endless and vast.

a normal ATX PSU works if you use the $7 adapter seen on ebay,  24pin to 6 pin dell adapter.

so with $7 and any PSU, you learn if mobo is ok,  for $7 whole dollars.

if time is endless even from china for $4. sold same thing.

you started this Post with ZERO history , examples

Ran for 5 years no problem now dead.

found this in a dumper or garage sale or ebay dead.

hand me down dead PC.

or?

history matters, is your FRONT PANEL I/o PANEL missing, many a dell will no work lacking that....

that front panel is USB ports and diagnostic LED, lacking that finding why it fails is way more hard or impossible.

the yellow LED on the mobo center means only 12vdc stanby power may be ok.

proves nothing else.

does the green button on rear of  PSU work?  BIST button, IIRC the name.

if not that green button, make fans turn on the PSU is toast most times (you need 1 stick of DDR RAM)

but this MOBO is full of VRM and if one goes bad mobo be dead.

now you know what can make this PC dead,  2nd PSU is most times best path

but time lags and costs always matter.  to most folks and that is your call.

did you bench test the PSU  yet

it only takes  paper clip jumper ask.  jump pin 7 to 8 see here.

let me show how

remove AC cord, push power button 3 times for 1 second.

remove PSU 2 DC power cables.  6 and 4

even whole PSU and put on bench

jumper 7 to 8

then put on AC cord.

the PSU turns on and all 12vdc wires go to 12v using a DMM meter set to volts.

there are 3  power pins on 8 pin plug.   pin 1 , 5 and 6

the 4 pin plug has two power pins, with 2 yellow wires, all are 12vdc.

with jumper present.

if found PC dead, check this?

is your power button tagged as? or with leading zero is ok too. D:P/N#

ypx0c

you not disable VBUS

that kills dead all USB ports ! why want that?

if you did the PC could never exit sleep, so is not allowed. to be killed that.

hi sir,

I tested power supply. on 8 pin connector:   Pin1=11.18v, pin5=12.08v, pin6=12.08v, pin4=4.96v

all these voltages are measured with pin7-8 shorted. when pin7-8 shorted PSU started and green light on back of psu glows solid green, fan of psu spins.

on 4 pin connector : both yellow wires shows 12v and back 0v 

motherboard button doesnt work, no led no sound.

i put 2gb ram but nothing happens. no display. i put new cmos battery, it shows voltage 3.12v.

it seems pc doesnt respond to power button. PC was working well. it is my friends pc. And suddenly stopped.

when i plug power supply nothing happens, no led glows neither orange nor white. nothing response to power button. it looks like South bridge failure. might be it not getting power? does usb and south bridge uses same power rail? or how can i chk that south bridge is getting power and working correctly.

ps. no display of cmos or nothing error msg is triggered or displayed.  looks like completely dead.

was working for friend, good, so is not hacked or worse. good.

USB on Dells  VBUS power , one is from 12v to 5v powerful VBUS controller, (and actual VBUS chips there)

No PCI cards, so its not that, and all RAMS sticks fail, most PCs have 2 , so it can run in DUAL channel mode for speed.

the power switch can be bad or mobo, seems its one of the other.  stripped down.

It might have got a lightening hit,

the mobo is  dirt cheap on ebay , $15 ?  is very very cheap.  like pack of CIGs in NYC cheap.

the 3020 is really Great PC, it is Haswell, Gen4 PC +H81, not chopped liver IMO.

the button theory is on my page, some buttons are colored wires and others are all black.

here is how to jumper power on this mOBO. (I do know) jump intermittently pin 3 to 6 here.(pull the button plug to it)

if that fails the mobo is dead, if single RAM only PC, then that, or bad CPU (rare if not molested)  .

good luck in your Quest !!!

Is SCH5553-NU  south bridge? 

It is said i/o controller and power button is connected to it.

Section near to it is not getting power