Desktop PC dead and "Strip Down" testing.
Or what is a Minimum system?
You are here because, the PC is dead, the PSU is dead, or runs for 1second and goes dead. (goes silent is dead for sure)
Power button dead, or blinks, its LED lamp acting odd, PC silent all fans dead? POST codes do not show up and no beep codes..
This is not about dead desktop monitors, .nor about plugging the monitor data cable in to the wrong port (VGA, DVI, DP, HDMI) if you have GPU card us only its PORTS.
This page is not how to fix NO BOOTS, but is about DEAD PC's. (no boot is simple, the boot order is wrong, or HDD bad or corrupted) Boot order wrong can be a bad RTC coin cell battery .
All PC's do this if you keep it for 10 years or more, even less years if it runs too hot and a real long time (hours used and for sure in a hot room)
The Macro list is simple:
Evidence seen or not or heard or not. (screen dead or errors on sceen or silent PC or not)
POST code errors, power on self test errors. LED codes BEEP codes or both are clear as day hard evidence. beep codes or LED status codes
The CD tray must eject with the button next to it now. (if not ?, power is dead)
Case lid removed, the center of the motherboard, LED going tells you at least standby power is good. (if not glowing PSU may be dead or no AC power to it)
If just the screen is dead and fans spin test the monitor on a 2nd PC next, and then make sure you are using the the correct GPU graphic port ,some PCs have 2 ports DP , main offline and GPU card DP only works now.
DP means display port, the video cable must be plugged into the GPU card if one is present. (card means PCI-e expansion slot cards)
The minimum is one each of ( MOBO, PSU, 1 DDR RAM stick , CPU) do not pull the CPU as 99% of NOOBs wreck the socket pins NOW. (kiss off MOBO if you did)
The goal is getting the BIOS screens working first.
If the PC wakes up now, you found your short, so replace the part that is shorted, (easy no?) wakes up can mean BIOS screens start working and is goal #1.
Wake up can mean also CPU fan starts working, or other prime evidence of live.
Most Desktops are super easy to Diagnose in this ordered list: this is the LONG PLAY VERSION, learn that what will be, will be.
PC's have shared resources if one thing shorts all things on the resource are now dead. (and the whole PC now dead)
AGAIN 1 more time the RTC coin cell battery not Dead, (below 2.9vdc is BAD) buy one or use a voltmeter to test it. (your call, but is a show stopper #1)
Last always last is to blame the failure on the motherboard. (some can cost $300, and new PSU is tried now. (do the PSU bench tests at # 14.)
If the new PSU is still dead?, the mobo is history.
A MOBO fail mostly for 2 reasons, lightening damage (hits) or ESD hits bad CAPS, or user abuse and #1 on the list of abuse is hotswapping any device or connector inside any PC.
What is a minimum system? REAL EXAMPLES and fully exposed to see what is going on here.
NOT saying to do this, only that the PC case is optional, one can bench test it all for sure. ( see my Dell 790 test bed here)
You can remove all SATA devices, HDD, SSD, M.2, DVD drives all drives removed and BIOS works (like the Dell F2 key or HP Esc key works.)
Power on any PC and quickly Hammer (geeks call it spamming) the BIOS key. (on Dell its F2, ESC for HP) F2 F2 F2 bingo BIOS POPS.
You can remove all RAM, but 1 stick in bank 0 and run as a single channel RAM bank sure can and test them 1 by 1 that way.
Most PC today (except below PC) needs no cards in the PCI-express slots, at all, even the GPU card, is removed and the on board, VGA port used, after a full reset.
Remove all PCI-e cards of any kind if PC has CORE i3 up, generation 1 Nehalem and up processor you need NO PCIe GPU at all.!
Remove all cables but 5 , AC power and the keyboard seen below and the VGA port to my VGA screen. (and 2 DC power cables seen below, 24pin and 4pin VRM power.)
On DELL PCs it will complain big time for other jacks unplugged, the front panel jack not there, and other, just ignore that, and get BIOS screens working first. (a goal #1 is BIOS)
Only use a known, good monitor LED, no monitor 2009 and older should be used there are dead or intermittant now, all are that old due to CCLF lamp death.
This photo below shows all (most) things missing and if still failing the GPU card is removed next, (we have and use old $5 GPU cards to test any PC, with SECURE/SAFE UEFI BOOT is OFF)
XW4600 HP workstation MOBO: I'm booted to USB stick demo live Windows 7 PE media, for testing there is no HDD here booted, one can use Linux DEMO mode to do the same thing,
Warning: no two mobo made have the same power pin out for the below connections front panel , there is no ATX spec standards on these pins ! (READ YOUR PC MANUAL)
These 2 power on pins are marked as , 1 is ground other is "power on" pin logic input, and is easy to jumper (momentary) The power panel or power button here is missing.
RTM read your manual find the 2 pins and jump it momentarily. example HP (pin 6/8)
HP Z600 Power on Pins P5 Jack is not in the HP manual, so is secret, until you look and see pins 16/17 or reverse engineer it.
Here is one more example of jumping my Dell 3020 (pin 3 jumped to 6)
The Dell 790 pin out is here.
My Dell 380 is covered here for the odd power on method, (I/O panel only switch)
Top and great makers of mobo , covers this topic of front panel wiring, ASUS, MSI, GIGABYTE
My Asus Z720-prime manual shows (Page 1-21) These pins clear as day. labeled PWR and GND.
Asus makes DIY mobo, and with great documents. (better than most makers if not all)
OEM PC makers do not, and do not document connectors. (all the non ATX connectors not covered, they will tell you just plug it in and not to worry)
The magic full power hard reset can in fact wake up a dead motherboard.
This one page is to help you get at least one BIOS working , and may take a new PSU.
My 790 Test bed PC, is naked as can be. benched. (running Furmark 3D APP) NO GPU card here, and we can test with 1 RAM DDR stick to. The extra fan is to keep South Bridge cooler.
The CPU fan is never dead. It must spin and on the Dells F2 key most get you BIOS main screen.
LAPTOP (LT) power structures are complex. (the actual PSU is hidden deep deep inside all LT)
Here is a page I made on Laptop power isolation testing.
The fake Desktops , AIO all in One can be diagnosed just like laptops. (skip the huge battery topic)
Some facts about PCs. ORDER, PCs BOOT in a serial order.; (basic basics 101 PC)
version 1. 12-12-2018 v2, 12-1-2019