Got a fault on the old ASUS desktop. Running Win7.

For ages at start up it has said CPU fan fault - but pressing F1 gets it
going and it's fine afterwards. The CPU fan seem to run normally, and I
tried replacing it.

But now, press the power button and it doesn't even get to the start up
banner.

Main fans and CPU fan running, though. But not the PS one. Press and hold
the reset button makes that run. Release and it stops.

Play around and it will sometimes boot but crashes soon afterwards.

Worth trying a new PS? Or would any fault in it be obvious?

--
*WHY IS IT CALLED TOURIST SEASON IF WE CAN'T SHOOT AT THEM?

Dave Plowman London SW
To e-mail, change noise into sound.

On 17/09/2019 15:55, Dave Plowman (News) wrote:
Got a fault on the old ASUS desktop. Running Win7.

For ages at start up it has said CPU fan fault - but pressing F1 gets it
going and it's fine afterwards. The CPU fan seem to run normally, and I
tried replacing it.

But now, press the power button and it doesn't even get to the start up
banner.

Main fans and CPU fan running, though. But not the PS one. Press and hold
the reset button makes that run. Release and it stops.

I suspect that with the reset button pressed the load on the PSU is
minimal and it croaks as soon as it is required to do any work.

Play around and it will sometimes boot but crashes soon afterwards.

Might be worth seeing if you can boot it and see the PSU voltages in the
advanced section of the BIOS or diagnostics (if they are provided).

Worth trying a new PS? Or would any fault in it be obvious?

Usually PSU's fail completely so that they blow an internal fuse or in
one case I had the magic smoke and fan assisted sparks coming out the
back. I unplugged it PDQ. Swapping the PSU is certainly worth a try.

--
Regards,
Martin Brown

In article ,
Martin Brown wrote:
Play around and it will sometimes boot but crashes soon afterwards.

Might be worth seeing if you can boot it and see the PSU voltages in the
advanced section of the BIOS or diagnostics (if they are provided).

Vcore 1.40v
3.3 3.32
5 5.02
12 12.22

All from the bios page.

They all look OK to me - but not sure what Vcore should be.

--
*The beatings will continue until morale improves *

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman (News) wrote:
Got a fault on the old ASUS desktop. Running Win7.

For ages at start up it has said CPU fan fault - but pressing F1 gets it
going and it's fine afterwards. The CPU fan seem to run normally, and I
tried replacing it.

But now, press the power button and it doesn't even get to the start up
banner.

Main fans and CPU fan running, though. But not the PS one. Press and hold
the reset button makes that run. Release and it stops.

Play around and it will sometimes boot but crashes soon afterwards.

Worth trying a new PS? Or would any fault in it be obvious?


Have you tried reseating the memory, replacing the back up battery,
checking any socketed devices are pushed home.


It is always worth vacuuming out the dust etc, especially from between heat
sink fins, while you are in there.

Ive recovered a surprising number of dead PCs with nothing more than the
above.

On 17/09/2019 16:25, Dave Plowman (News) wrote:
In article ,
Martin Brown wrote:
Play around and it will sometimes boot but crashes soon afterwards.

Might be worth seeing if you can boot it and see the PSU voltages in the
advanced section of the BIOS or diagnostics (if they are provided).

Vcore 1.40v
3.3 3.32
5 5.02
12 12.22

All from the bios page.

They all look OK to me - but not sure what Vcore should be.


Maybe remove any additional PCI/(e) cards that are optional
to reduce the loading and see what happens.

Doesn't it give a series of audible beeps that indicates
what the fault could be ?.

Good time to upgrade to a 80+ PSU to save on leccy,
assuming it is standard PSU size.

If the national voltage and frequency went down too low
back in august, I wonder how many 'odd' failings are
occuring all around the country with all manner of
stuff.

On 17/09/2019 17:14, Andrew wrote:
On 17/09/2019 16:25, Dave Plowman (News) wrote:
In article ,
Â*Â*Â* Martin Brown wrote:
Play around and it will sometimes boot but crashes soon afterwards.

Might be worth seeing if you can boot it and see the PSU voltages in the
advanced section of the BIOS or diagnostics (if they are provided).

Vcore 1.40v
3.3Â*Â* 3.32
5Â*Â*Â*Â* 5.02
12Â*Â*Â* 12.22

All from the bios page.

They all look OK to me - but not sure what Vcore should be.


Maybe remove any additional PCI/(e) cards that are optional
to reduce the loading and see what happens.

Doesn't it give a series of audible beeps that indicates
what the fault could be ?.

But not if the PSU itself goes into thermal shutdown under load.

Good time to upgrade to a 80+ PSU to save on leccy,
assuming it is standard PSU size.

If the national voltage and frequency went down too low
back in august, I wonder how many 'odd' failings are
occuring all around the country with all manner of
stuff.

Switched mode PSU's tolerate brownouts remarkably well. My recollection
from the old days of tube based VDUs is that the monitor would fail to
light up the screen before the PC stopped working when we did voltage
tolerance tests on things expected to have a rough service life.

--
Regards,
Martin Brown

Have you checked the bios?
I had a similar issue and a driver for the fan had vanished for some
unknown reason. If the processor is overheating that fast though, could the
processor be faulty or the thermal contact with the heat sinc be bad?
Have you vacuumed out the heat sink?
Brian

--
----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"Dave Plowman (News)" wrote in message
...
Got a fault on the old ASUS desktop. Running Win7.

For ages at start up it has said CPU fan fault - but pressing F1 gets it
going and it's fine afterwards. The CPU fan seem to run normally, and I
tried replacing it.

But now, press the power button and it doesn't even get to the start up
banner.

Main fans and CPU fan running, though. But not the PS one. Press and hold
the reset button makes that run. Release and it stops.

Play around and it will sometimes boot but crashes soon afterwards.

Worth trying a new PS? Or would any fault in it be obvious?

--
*WHY IS IT CALLED TOURIST SEASON IF WE CAN'T SHOOT AT THEM?

Dave Plowman London SW
To e-mail, change noise into sound.

Yes also one dodgy stick of ram can make the pc shut down almost as soon as
it comes on.
Brian

--
----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"Brian Reay" wrote in message
...
Dave Plowman (News) wrote:
Got a fault on the old ASUS desktop. Running Win7.

For ages at start up it has said CPU fan fault - but pressing F1 gets it
going and it's fine afterwards. The CPU fan seem to run normally, and I
tried replacing it.

But now, press the power button and it doesn't even get to the start up
banner.

Main fans and CPU fan running, though. But not the PS one. Press and hold
the reset button makes that run. Release and it stops.

Play around and it will sometimes boot but crashes soon afterwards.

Worth trying a new PS? Or would any fault in it be obvious?


Have you tried reseating the memory, replacing the back up battery,
checking any socketed devices are pushed home.


It is always worth vacuuming out the dust etc, especially from between
heat
sink fins, while you are in there.

I've recovered a surprising number of dead PCs with nothing more than the
above.

On 17/09/2019 15:55, Dave Plowman (News) wrote:
Got a fault on the old ASUS desktop. Running Win7.

For ages at start up it has said CPU fan fault - but pressing F1 gets it
going and it's fine afterwards. The CPU fan seem to run normally, and I
tried replacing it.

But now, press the power button and it doesn't even get to the start up
banner.

Main fans and CPU fan running, though. But not the PS one. Press and hold
the reset button makes that run. Release and it stops.

Play around and it will sometimes boot but crashes soon afterwards.

Worth trying a new PS? Or would any fault in it be obvious?


There can be duff capacitors in the PSU which cause problems like that.


--
Michael Chare

"Dave Plowman (News)" wrote in message
...
Got a fault on the old ASUS desktop. Running Win7.

For ages at start up it has said CPU fan fault - but pressing F1 gets it
going and it's fine afterwards. The CPU fan seem to run normally, and I
tried replacing it.

But now, press the power button and it doesn't even get to the start up
banner.

Main fans and CPU fan running, though. But not the PS one. Press and hold
the reset button makes that run. Release and it stops.

Play around and it will sometimes boot but crashes soon afterwards.

That sort of quirky result is often due to bad caps on the motherboard.
Easy to check by eye, look for electros with bulges on the top.

Worth trying a new PS?

Very unusual for a bad PS to produce those symptoms,
It can do but if it does, its usually due to the 12V supply
being way out but that’s easy to check with a multimeter.

Or would any fault in it be obvious?

Not always but it wouldn’t normally produce those
symptoms if it was the PS. The PS fan effect is unusual,
measure the voltage its getting with the reset button
being held in and when its released when the fan is going
and when its not. A few systems do shut down if the PS
fan can be seen to not be rotating,. but that’s uncommon.

"Dave Plowman (News)" wrote in message
...
In article ,
Martin Brown wrote:
Play around and it will sometimes boot but crashes soon afterwards.

Might be worth seeing if you can boot it and see the PSU voltages in the
advanced section of the BIOS or diagnostics (if they are provided).

Vcore 1.40v
3.3 3.32
5 5.02
12 12.22

All from the bios page.

They all look OK to me - but not sure what Vcore should be.

It wont be the Vcore producing the PS fan effect.

"Brian Reay" wrote in message
...
Dave Plowman (News) wrote:
Got a fault on the old ASUS desktop. Running Win7.

For ages at start up it has said CPU fan fault - but pressing F1 gets it
going and it's fine afterwards. The CPU fan seem to run normally, and I
tried replacing it.

But now, press the power button and it doesn't even get to the start up
banner.

Main fans and CPU fan running, though. But not the PS one. Press and hold
the reset button makes that run. Release and it stops.

Play around and it will sometimes boot but crashes soon afterwards.

Worth trying a new PS? Or would any fault in it be obvious?

Have you tried reseating the memory, replacing the back up
battery, checking any socketed devices are pushed home.

Those wouldnt produce the PS fan effect.

It is always worth vacuuming out the dust etc, especially
from between heat sink fins, while you are in there.

Ditto.

Ive recovered a surprising number of dead
PCs with nothing more than the above.

Sure, but those didnt have that PS fan effect.

On Tue, 17 Sep 2019 17:14:54 +0100, Andrew wrote:

On 17/09/2019 16:25, Dave Plowman (News) wrote:
In article ,
Martin Brown wrote:
Play around and it will sometimes boot but crashes soon afterwards.

Might be worth seeing if you can boot it and see the PSU voltages in the
advanced section of the BIOS or diagnostics (if they are provided).

Vcore 1.40v
3.3 3.32
5 5.02
12 12.22

All from the bios page.

They all look OK to me - but not sure what Vcore should be.


Maybe remove any additional PCI/(e) cards that are optional
to reduce the loading and see what happens.

Doesn't it give a series of audible beeps that indicates
what the fault could be ?.

Good time to upgrade to a 80+ PSU to save on leccy,
assuming it is standard PSU size.

If the national voltage and frequency went down too low
back in august, I wonder how many 'odd' failings are
occuring all around the country with all manner of
stuff.

What is this voltage/frequency event you're referring to? In my experience you can't rely on the mains being solid at any time. After all, it's supplying thousands of houses in your area with loads changing all the time, you can't reasonably expect them to keep it perfectly stable. Any appliance you use must be able to accept some changes. I put my computer (and peripherals, and my house lighting) onto a UPS. Had zero problems since, plus the LED lights in my house last 4 times longer.

On Tue, 17 Sep 2019 17:33:50 +0100, Martin Brown wrote:

On 17/09/2019 17:14, Andrew wrote:
On 17/09/2019 16:25, Dave Plowman (News) wrote:
In article ,
Martin Brown wrote:
Play around and it will sometimes boot but crashes soon afterwards.

Might be worth seeing if you can boot it and see the PSU voltages in the
advanced section of the BIOS or diagnostics (if they are provided).

Vcore 1.40v
3.3 3.32
5 5.02
12 12.22

All from the bios page.

They all look OK to me - but not sure what Vcore should be.


Maybe remove any additional PCI/(e) cards that are optional
to reduce the loading and see what happens.

Doesn't it give a series of audible beeps that indicates
what the fault could be ?.

But not if the PSU itself goes into thermal shutdown under load.

Good time to upgrade to a 80+ PSU to save on leccy,
assuming it is standard PSU size.

If the national voltage and frequency went down too low
back in august, I wonder how many 'odd' failings are
occuring all around the country with all manner of
stuff.

Switched mode PSU's tolerate brownouts remarkably well. My recollection
from the old days of tube based VDUs is that the monitor would fail to
light up the screen before the PC stopped working when we did voltage
tolerance tests on things expected to have a rough service life.

Most computer PSUs I've used will shut off after a 1 second powercut. You really need a UPS.

RAM is easily tested with a freeware self booting program called memtest. Faulty RAM usually causes blue screens.


On Tue, 17 Sep 2019 18:54:38 +0100, Brian Gaff wrote:

Yes also one dodgy stick of ram can make the pc shut down almost as soon as
it comes on.
Brian

Comparing the temperature of the CPU reported by the motherboard with the temperature you can feel with your finger on the heatsink will tell you if it's conducting properly. I had a PC where the CPU temperature was reported as 90C, yet the heatsink felt cold. One of the clips had come undone, the heatsink wasn't contacting the CPU very well at all.

On Tue, 17 Sep 2019 18:49:47 +0100, Brian Gaff wrote:

Have you checked the bios?
I had a similar issue and a driver for the fan had vanished for some
unknown reason. If the processor is overheating that fast though, could the
processor be faulty or the thermal contact with the heat sinc be bad?
Have you vacuumed out the heat sink?
Brian

On Tue, 17 Sep 2019 19:53:58 +0100, Michael Chare wrote:

On 17/09/2019 15:55, Dave Plowman (News) wrote:
Got a fault on the old ASUS desktop. Running Win7.

For ages at start up it has said CPU fan fault - but pressing F1 gets it
going and it's fine afterwards. The CPU fan seem to run normally, and I
tried replacing it.

But now, press the power button and it doesn't even get to the start up
banner.

Main fans and CPU fan running, though. But not the PS one. Press and hold
the reset button makes that run. Release and it stops.

Play around and it will sometimes boot but crashes soon afterwards.

Worth trying a new PS? Or would any fault in it be obvious?

There can be duff capacitors in the PSU which cause problems like that.

Usually spottable as they bulge or burst. Same happens in LCD TVs.

"Michael Chare" wrote in message
...
On 17/09/2019 15:55, Dave Plowman (News) wrote:
Got a fault on the old ASUS desktop. Running Win7.

For ages at start up it has said CPU fan fault - but pressing F1 gets it
going and it's fine afterwards. The CPU fan seem to run normally, and I
tried replacing it.

But now, press the power button and it doesn't even get to the start up
banner.

Main fans and CPU fan running, though. But not the PS one. Press and hold
the reset button makes that run. Release and it stops.

Play around and it will sometimes boot but crashes soon afterwards.

Worth trying a new PS? Or would any fault in it be obvious?


There can be duff capacitors in the PSU which cause problems like that.

More likely on the motherboard with the cpu fan warning tho.

On Wed, 18 Sep 2019 05:49:56 +1000, jeikppkywk, better known as cantankerous
trolling senile geezer Rodent Speed, wrote:


Vcore 1.40v
3.3 3.32
5 5.02
12 12.22

All from the bios page.

They all look OK to me - but not sure what Vcore should be.

It wont be the Vcore producing the PS fan effect.

Are you sure, senile idiot? Senilely sure, again? G

--
addressing nym-shifting senile Rodent:
"You on the other hand are a heavyweight bull****ter who demonstrates
your particular prowess at it every day."
MID:

On Wed, 18 Sep 2019 05:52:04 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

Those wouldn¢t produce the PS fan effect.

It is always worth vacuuming out the dust etc, especially
from between heat sink fins, while you are in there.

Ditto.

I¢ve recovered a surprising number of dead
PCs with nothing more than the above.

Sure, but those didn¢t have that PS fan effect.

Can't you just shut your senile gob for a while, you endlessly bull****ting
senile bull**** artist?

--
about senile Rot Speed:
"This is like having a conversation with someone with brain damage."
MID:

On Wed, 18 Sep 2019 06:24:27 +1000, jeikppkywk, better known as cantankerous
trolling senile geezer Rodent Speed, wrote:


There can be duff capacitors in the PSU which cause problems like that.

More likely on the motherboard with the cpu fan warning tho.

How MUCH more "likely", you endlessly blithering senile wisenheimer?

--
Richard addressing Rot Speed:
"**** you're thick/pathetic excuse for a troll."
MID:

On Wed, 18 Sep 2019 05:41:25 +1000, jeikppkywk, better known as cantankerous
trolling senile geezer Rodent Speed, wrote:

"Dave Plowman (News)" wrote in message
...
Got a fault on the old ASUS desktop. Running Win7.

For ages at start up it has said CPU fan fault - but pressing F1 gets it
going and it's fine afterwards. The CPU fan seem to run normally, and I
tried replacing it.

But now, press the power button and it doesn't even get to the start up
banner.

Main fans and CPU fan running, though. But not the PS one. Press and hold
the reset button makes that run. Release and it stops.

Play around and it will sometimes boot but crashes soon afterwards.

That sort of quirky result is often due to bad caps on the motherboard.
Easy to check by eye, look for electros with bulges on the top.

LOL ...the "all-knowing", senile "mastermind" from Oz just struck again!

FLUSH rest of the senile asshole's usual troll****

--
Website (from 2007) dedicated to the 85-year-old trolling senile
cretin from Oz:
https://www.pcreview.co.uk/threads/r...d-faq.2973853/

On 17/09/2019 15:55, Dave Plowman (News) wrote:
Got a fault on the old ASUS desktop. Running Win7.

For ages at start up it has said CPU fan fault - but pressing F1 gets it
going and it's fine afterwards. The CPU fan seem to run normally, and I
tried replacing it.

It could be the RPM sensor is not working (either on the fan, or the
logic for reading it on the motherboard. You may be able to change the
fan type in the BIOS such that it does not expect it to be a three wire
type.

But now, press the power button and it doesn't even get to the start up
banner.

Main fans and CPU fan running, though. But not the PS one. Press and hold
the reset button makes that run. Release and it stops.

That sounds more like a PSU problem.

Play around and it will sometimes boot but crashes soon afterwards.

That could be overheating - either CPU or PSU.

Worth trying a new PS? Or would any fault in it be obvious?

I would say its worth a try.



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In article ,
John Rumm wrote:
On 17/09/2019 15:55, Dave Plowman (News) wrote:
Got a fault on the old ASUS desktop. Running Win7.

For ages at start up it has said CPU fan fault - but pressing F1 gets it
going and it's fine afterwards. The CPU fan seem to run normally, and I
tried replacing it.

It could be the RPM sensor is not working (either on the fan, or the
logic for reading it on the motherboard. You may be able to change the
fan type in the BIOS such that it does not expect it to be a three wire
type.

The BIOS does give the fan RPM. If the tach signal failed, I'd expect that
to be rubbish? But it looks a sensible speed to me.

But now, press the power button and it doesn't even get to the start up
banner.

Main fans and CPU fan running, though. But not the PS one. Press and
hold the reset button makes that run. Release and it stops.

That sounds more like a PSU problem.

I've ordered up a new one.

Play around and it will sometimes boot but crashes soon afterwards.

That could be overheating - either CPU or PSU.

Worth trying a new PS? Or would any fault in it be obvious?

I would say its worth a try.

--
*When a clock is hungry it goes back four seconds*

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" wrote in message
...
In article ,
John Rumm wrote:
On 17/09/2019 15:55, Dave Plowman (News) wrote:
Got a fault on the old ASUS desktop. Running Win7.

For ages at start up it has said CPU fan fault - but pressing F1 gets
it
going and it's fine afterwards. The CPU fan seem to run normally, and I
tried replacing it.

It could be the RPM sensor is not working (either on the fan, or the
logic for reading it on the motherboard. You may be able to change the
fan type in the BIOS such that it does not expect it to be a three wire
type.

The BIOS does give the fan RPM. If the tach signal failed, I'd
expect that to be rubbish? But it looks a sensible speed to me.

Maybe its just slow to start and that’s why hitting F1 sees it fine later.

But now, press the power button and it doesn't even get to the start up
banner.

Main fans and CPU fan running, though. But not the PS one. Press and
hold the reset button makes that run. Release and it stops.

That sounds more like a PSU problem.

I've ordered up a new one.

Play around and it will sometimes boot but crashes soon afterwards.

That could be overheating - either CPU or PSU.

Worth trying a new PS? Or would any fault in it be obvious?

I would say its worth a try.

Dave Plowman wrote:

Worth trying a new PS? Or would any fault in it be obvious?

Disconnect the PSU's 20 or 24 pin connector from the motherboard, short
the green pin (PS_ON) to any black pin (GND) and it should turn on, if
it doesn't it's faulty.

Monitor the grey pin (PWR_OK) it should go from 0V to 5V within about
half a second to tell the motherboard that the PSU deems itself to be
working within limits, if it goes low the motherboard will shut off the PSU.

On Wed, 18 Sep 2019 10:02:00 +1000, jeikppkywk, better known as cantankerous
trolling senile geezer Rodent Speed, wrote:


The BIOS does give the fan RPM. If the tach signal failed, I'd
expect that to be rubbish? But it looks a sensible speed to me.

Maybe its just slow to start and that¢s why hitting F1 sees it fine later.

More bull**** from the resident "heavyweight bull****ter", senile Rodent
himself.

--
addressing nym-shifting senile Rodent:
"You on the other hand are a heavyweight bull****ter who demonstrates
your particular prowess at it every day."
MID:

In article ,
Andy Burns wrote:
Dave Plowman wrote:

Worth trying a new PS? Or would any fault in it be obvious?

Disconnect the PSU's 20 or 24 pin connector from the motherboard, short
the green pin (PS_ON) to any black pin (GND) and it should turn on, if
it doesn't it's faulty.

It already turns on via the button. Fans run and the DVD LEDs light up. So
it has 12v and 5v. DVDs will also open and close and spin up. No LED
showing disc activity, though.

Monitor the grey pin (PWR_OK) it should go from 0V to 5V within about
half a second to tell the motherboard that the PSU deems itself to be
working within limits, if it goes low the motherboard will shut off the
PSU.

It doesn't shut it down.

As I said, the only strange thing (other than the motherboard appearing
totally dead) is the PS fan doesn't run until the reset button is pressed.
Then stops when released.

--
*Out of my mind. Back in five minutes.

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman wrote:

It already turns on via the button.
It doesn't shut it down.

I was trying to eliminate the motherboard from the equation, not much
point buying a new PSU to check with, if it's not the problem ...

On Tue, 17 Sep 2019 21:02:22 +0100, Commander Kinsey wrote:

Switched mode PSU's tolerate brownouts remarkably well.

Most computer PSUs I've used will shut off after a 1 second powercut.

Powercut != brownout. Most computer power supplies will happily run
on any thing from 100 V to 250 V AC or DC.

This abilty of SMPSU's to run on almost anything confused the heck
out of me when the supply dropped to about 125 V at 0400 one morning
An ice storm brought the distribution lines down in half a dozen or
so places and snapped a few poles. Some bits of kit were on and quite
happy, others off.

--
Cheers
Dave.

On Wed, 18 Sep 2019 20:32:06 +0100, Dave Liquorice wrote:

On Tue, 17 Sep 2019 21:02:22 +0100, Commander Kinsey wrote:

Switched mode PSU's tolerate brownouts remarkably well.

Most computer PSUs I've used will shut off after a 1 second powercut.

Powercut != brownout. Most computer power supplies will happily run
on any thing from 100 V to 250 V AC or DC.

Perhaps so, but it's not usually just one or the other. It most likely drops a random amount unevenly, possibly getting under the 100V for part of that time.

This abilty of SMPSU's to run on almost anything confused the heck
out of me when the supply dropped to about 125 V at 0400 one morning
An ice storm brought the distribution lines down in half a dozen or
so places and snapped a few poles. Some bits of kit were on and quite
happy, others off.

How come the mini SMPSUs in my LED lighting make the LEDs go noticeably dimmer when the voltage drops a bit? (Like 10-20V) Yet they are rated 85-265V. Or are they actually just dimming for a fraction of a second before compensating, and my eye detects this as dimming? I thought the way SMPSUs worked, the output wouldn't vary one bit?

"Commander Kinsey" wrote in message
news
On Wed, 18 Sep 2019 20:32:06 +0100, Dave Liquorice
wrote:

On Tue, 17 Sep 2019 21:02:22 +0100, Commander Kinsey wrote:

Switched mode PSU's tolerate brownouts remarkably well.

Most computer PSUs I've used will shut off after a 1 second powercut.

Powercut != brownout. Most computer power supplies will happily run
on any thing from 100 V to 250 V AC or DC.

Perhaps so,

No perhaps about it, certainly so.

but it's not usually just one or the other.

He didn't say that it was.

It most likely drops a random amount unevenly,

The PS doesn't care.

possibly getting under the 100V for part of that time.

Hardly ever gets that low.

This abilty of SMPSU's to run on almost anything confused the heck out of
me when the supply dropped to about 125 V at 0400 one morning An ice
storm brought the distribution lines down in half a dozen or so places
and snapped a few poles. Some bits of kit were on and quite happy, others
off.

How come the mini SMPSUs in my LED lighting make the LEDs go noticeably
dimmer when the voltage drops a bit? (Like 10-20V) Yet they are rated
85-265V.

**** chinese design. My Hues don't.

Or are they actually just dimming for a fraction of a second before
compensating, and my eye detects this as dimming?

They don't compensate.

I thought the way SMPSUs worked, the output wouldn't vary one bit?

Correct with a decent design.

On Wed, 18 Sep 2019 20:32:06 +0100 (BST), Dave Liquorice, another brain
damaged, troll-feeding senile idiot, blathered again:


so places and snapped a few poles. Some bits of kit were on and quite
happy, others off.

You've just made the sociopathic troll VERY happy, troll-feeding senile
idiot! BG

On Thu, 19 Sep 2019 06:26:41 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

FLUSH the two prize idiots' latest idiotic drivel unread

....and nothing's left!

--
Marland answering senile Rodent's statement, "I don't leak":
"That¢s because so much **** and ****e emanates from your gob that there is
nothing left to exit normally, your arsehole has clammed shut through disuse
and the end of prick is only clear because you are such a ******."
Message-ID:

On 18/09/2019 20:41, Commander Kinsey wrote:
On Wed, 18 Sep 2019 20:32:06 +0100, Dave Liquorice
wrote:

On Tue, 17 Sep 2019 21:02:22 +0100, Commander Kinsey wrote:

Switched mode PSU's tolerate brownouts remarkably well.

Most computer PSUs I've used will shut off after a 1 second powercut.

Powercut != brownout. Most computer power supplies will happily run
on any thing from 100 V to 250 V AC or DC.

Perhaps so, but it's not usually just one or the other.* It most likely
drops a random amount unevenly, possibly getting under the 100V for part
of that time.

The most common situation round here is that one of the three phases
goes open circuit and neutral floats up to a voltage mid way between the
two remaining live phases. So 240 vac drops to around 200v. LED lights
and PC's don't even notice this but filament bulbs glow dim orange.

This abilty of SMPSU's to run on almost anything confused the heck
out of me when the supply dropped to about 125 V at 0400 one morning
An ice storm brought the distribution lines down in half a dozen or
so places and snapped a few poles. Some bits of kit were on and quite
happy, others off.

How come the mini SMPSUs in my LED lighting make the LEDs go noticeably
dimmer when the voltage drops a bit?* (Like 10-20V)* Yet they are rated
85-265V.* Or are they actually just dimming for a fraction of a second
before compensating, and my eye detects this as dimming?* I thought the
way SMPSUs worked, the output wouldn't vary one bit?

Decent ones don't. The cheap and nasty ones might. Most will work OK
with anything above about 100v just drawing more current to compensate.

--
Regards,
Martin Brown

On Thu, 19 Sep 2019 10:18:56 +0100, Martin Brownnoser, another troll-feeding
senile idiot, blathered again:


Decent ones don't. The cheap and nasty ones might. Most will work OK
with anything above about 100v just drawing more current to compensate.

Decent people don't feed that sociopathic Scottish ****** and troll, senile
idiot! tsk

In article ,
Andy Burns wrote:
Dave Plowman wrote:

It already turns on via the button.
It doesn't shut it down.

I was trying to eliminate the motherboard from the equation, not much
point buying a new PSU to check with, if it's not the problem ...

The fact that the PS fans don't run at switch on seems odd. But do when
you press the reset button.

--
*Corduroy pillows are making headlines.

Dave Plowman London SW
To e-mail, change noise into sound.

On Thu, 19 Sep 2019 10:18:56 +0100, Martin Brown wrote:

On 18/09/2019 20:41, Commander Kinsey wrote:
On Wed, 18 Sep 2019 20:32:06 +0100, Dave Liquorice
wrote:

On Tue, 17 Sep 2019 21:02:22 +0100, Commander Kinsey wrote:

Switched mode PSU's tolerate brownouts remarkably well.

Most computer PSUs I've used will shut off after a 1 second powercut.

Powercut != brownout. Most computer power supplies will happily run
on any thing from 100 V to 250 V AC or DC.

Perhaps so, but it's not usually just one or the other. It most likely
drops a random amount unevenly, possibly getting under the 100V for part
of that time.

The most common situation round here is that one of the three phases
goes open circuit and neutral floats up to a voltage mid way between the
two remaining live phases. So 240 vac drops to around 200v. LED lights
and PC's don't even notice this but filament bulbs glow dim orange.

You must have some weird supplies there. I thought they were all similar to what I have. There's a substation across the road from me which takes 3 phase 11kV in. It outputs 3 phase 240V. The neutral is grounded at the substation with a big stick. Each house (they alternate between phase 1, 2, 3 as you go along the street) gets a phase and the neutral, supplied to the house with an armoured cable. A 100 amp live carrying a phase, surrounded by the armour which is neutral (and ground). My neutral can never be anything but zero volts, because of the big stick. Mind you, I guess if the supply to the substation lost one of the three 11kV phases, some weird **** might happen to th voltage on my 240V phase. But I'd expect breakers or something to detect that and shut it off before someone gets unusual voltages.

This abilty of SMPSU's to run on almost anything confused the heck
out of me when the supply dropped to about 125 V at 0400 one morning
An ice storm brought the distribution lines down in half a dozen or
so places and snapped a few poles. Some bits of kit were on and quite
happy, others off.

How come the mini SMPSUs in my LED lighting make the LEDs go noticeably
dimmer when the voltage drops a bit? (Like 10-20V) Yet they are rated
85-265V. Or are they actually just dimming for a fraction of a second
before compensating, and my eye detects this as dimming? I thought the
way SMPSUs worked, the output wouldn't vary one bit?

Decent ones don't. The cheap and nasty ones might. Most will work OK
with anything above about 100v just drawing more current to compensate.

Perhaps I'm just seeing a very temporary dimming, the human eye isn't that accurate. If they can take 85V, then they can't dim much by dropping from 240 to 220. It's just I thought it would be impossible for a SMPSU to do that. In its simplest form, it's charging a bulk capacitor to 340V DC, or less if your input AC is lower. Then that's passed in a controlled manner by an IC and transistor to the lower voltage output capacitor (in my case 70VDC for the LEDs). Surely if the bulk capacitor lowered in voltage due to a brownout, the duty cycle for transferring power to the output capacitor would just increase to compensate?

Dave Plowman (News) wrote:

The fact that the PS fans don't run at switch on seems odd. But do when
you press the reset button.

yes, a delay on the cpu/motherboards fans I could understand, if the SMM
takes a while to initialise, but not generally the PSU fan.

On 19/09/2019 16:40, Andy Burns wrote:
Dave Plowman (News) wrote:

The fact that the PS fans don't run at switch on seems odd. But do when
you press the reset button.

yes, a delay on the cpu/motherboards fans I could understand, if the SMM
takes a while to initialise, but not generally the PSU fan.

If you unplug all the PS connectorss from the MB, disks etc
and turn it on does the PS fan blow, or does it need a load
to do anything ?.