Stand by When my pc goes into stand by everthing shuts down except main cooling fan which just keeps running tried different settings new mobo fitted recently hope you can help

When you say the the furnace re-starts 8 times before shut down, what is cycling 8 times? just the indoor blower or is the main burner re-firing 8 times? If it's only the fan it sounds like the fan control.

dead PC, DESKTOP PC ,as old as 2009.
the fans tells you the PSU shut off, for cause.
fans, so you saw all fans turn off or just 1. or 2 of 3.
my pc has 4 fans many have 3;
CPU fan stops ,cpu overheats , PC goes slow or dead. clean the lint off it.
GPU fan , video goes dead. if it overheats.
PSU fan is inside the PSU if it goes bad, PSU is bad.
no monitor stated, is it CRT or LCD is it 15 years old.
if the monitor is 2002 or newer the OSD screen works
even with PC turned off, press the select button see that OSD screen ? telling you the monitor is not dead in 1second flat;
i caN NOT understand why the HDD lamp glows,
if the PSU shuts off , most LEDs go dead, on my PC
the standby LED on the MOBO glows, unless you pull the PSU power cord.
your HP PC came with 9 different mobo, during its production run.
at least. so answers come harder from that reason.

here are some simple tests.
test 1
power on, hear fans run
does the DVD drive (or cd) button eject work,.?
do all fans not just 1 or 2 worK? look for all fans clean the lent out
or things will overheat,
PSU can be bench tested or in the PC case.
using a jumper wire, even the HP service manual covers that.

power on the PC (after keeping monitor on for 5 full minutes)
test 2
the Screen must say, "hit ESC key to enter HP setup" BIOS.
press the ESC key on the monitor
if no text shows up that is a dead PC< "text above missing{"
if the PC told you to hit another key do so.
The ESC key , activates the BIOS brain. this cause
all those pages to work as seen in your service manual;.
if BIOS is dead that is a bad PSU (monitor ok)
or CPU is overheated.
bad ram, take all sticks out and test 1 by 1, ask how. !
The PSU will shut down on up to 12 or more faults
but never shuts down the standby power bus. unless AC line pulled.
IF the PSU has fan as most do this is the first place I look.



try this guide
https://support.hp.com/us-en/document/bph06788

Hello
I thinks you may be right. All plasma and LCD panel tVs will have cooling fans at the top side. Plasma screens will heat up much more, and if cooling fans stops work, of has damaged, the set will overheat, and awill automatically shut down; because there is a overheat sensor fitted inside it, will sense the heat, and if the set overheats, it will send a signal to the main system control fo the TV; which in turn shut down the whole system. look fans for proper working. If not replace them. OK.

Is this a new hvac system? A new furnace can work differently than your old one. Does it shut off after a minute or two or continue to run? If it continues to run then call that professional back and let him fix it. If it shuts down after a minute or two then it is a feature of the new thermostat to squeeze all of the cool it can from the a/c coil and ductwork.Some of them have settings that you can adjust for blower delay on and off, read the manual that came with the t-stat and see if it does.

You should look for the following answers.
(1) Are you operating your laptop in a in a hot and dusty environment (If yes you should know that computers do not like hot and dusty environments and they shut down to avoid a complete burn out of the machine more over the dust particles also can destroy the hardware and block internal fan ventilation ducts in between the CPU and the fan).
(2) When the your laptop PC shuts down place your hand underneath the laptop and try to feel hot spots. If you find areas unusually heated then this is the main cause of the shut down.
(3) If just after the shut down and a good usage the Laptop is cool then underneath than overheating shut down might not be the case.
If you determined that heating is the cause and you cannot change your environment than you should look for other heavy duty laptops that are robustly designed for hot environments.
I do not think that resting the BIOS can cause this.

step 2 the TECH uses a voltmeter and checks all wires on PSU for correct voltage.

PSU in Desktop dead, my guess fans dead too right>
you never said, what it does inside PC ,except nothing
does nothing mean dead silence?
the fan must run for 1second, then goes off.
a 1 second run tells me the PC power switch told the MOBO to turn on and in turn it tells the PSU to turn on,
the PSU then turns on for at least 1second,and if the voltages are ok
then the PSU stays on, else off goes.

15 and 16?
the 20 pin older supplies those are both ground
but 24 pin ATX pins are correct there.
the voltages are here.
https://en.wikipedia.org/wiki/ATX


There are 2 causes, of dead power button.
1: the buttons 2 wire cable ends fell off. at button or PC mobo.
2: The PSU is bad.
3: the MOBO is bad.

The mobo can also shut off any PSU, if the PSU fails
or it sees the regulators in the MOBO fail.
the Desktop runs on many power rails.
some in the PSU, others on the MOBO.
THe mobo creates special low voltage for the CPU.

the power good pin, does that #8,
One way to see if the MOBO is overload
is to remove things from it, I start at RAM
lacking a voltmeter, this is very hard to fix any thing electric.
only guessing or pulling objects PC can find shorts.
pull all power cables there, hdd, power, cdrom.
all things that use red/yellow wires.
all SATA cables, all USB , then ram. even a fan can short
a good tech keeps an open mind, and finds why the PSU shut down.
in most cases, the PSU is bad. but not always.

This is a feature, of ATX it keeps you from blowing up say a
$300 microprocessor.... or fancy gaming Video card (have one)?
yes, pull the video card too.

Sure sounds like a motherboard issue to me!

FIRST....... Make sure you remove the stock thermal compund (pasty/sticky stuff) from the bottom of the heat sink as well as from the top of the cpu.........

Second APPLY some ARCTIC SILVER 5 compound-ust a thin coat of it over the top of the cpu......use an old credit card.....keep it ff the sides and bottom though......it's important not to use too much........one little tube will do anywhere from 3 to 5 CPUs...!!!
(stock thermal paste/thermal compunds......**** BADLY and can cause a cpu to burn up)

reseat (properly) the cpu and carefull

Now make sure you're 24 pin or 20+4Pin Power connectors are connected, as well as your fans..........disconnect all your SATA Devices, and remove everything but the video card , CPU, and fans.......Now it should post (if all your jumpers are set correctly...........


IF it still doesn't post, remove the video card and reboot.

If it doesn't beep at all......... You have one of 2 things.........A DEAD CPU, or a DEAD MOBO

remove all hardware except RAM n CPU and then try it if the system gives you a disply then add all hardware 1 by 1 and keep checkin this way you can find the problem with the harware compatibility if the system wont disply then check the mobo for RAMs and CPU respectively if the problem presists then you have the BAD BOARD.-

Please check your processors temperature (h/w monitor, 'Hardware Monitor') in the bios settings, and refer to your mobo manual, sounds like an overheating problem. Try running your pc with the side off, for a few days see if it occurs again, check fans for being clogged up with dust, if overheating is the problem,check ide cables are'nt blocking air flow and fit a case fan, very cheap to buy