Bad wiring?

  • Thread starter Thread starter Thip
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Thip

Not good at posting from my phone,sorry! But here goes...comp is in the den, had one here for 8+ years. I blew out a fairly new PSU 2 months ago. Replaced it, and today the comp died again. I set up an old HP to use, and now it's not booting. Fans turn but not on the PSU. I've tried various outlets in the room, swapped power cords, and the HP was not plugged into the same outlet as my regular comp. Does this sound like bad wiring? We've hadsome monster thunderstorms and a recent lightning hit nearby, but they came after my first PSU went. Any help would be really appreciated!
 
Thip said:
Not good at posting from my phone,sorry!
But here goes...comp is in the den, had one here
for 8+ years. I blew out a fairly new PSU 2 months
ago. Replaced it, and today the comp died again.
I set up an old HP to use, and now it's not booting.
Fans turn but not on the PSU. I've tried various
outlets in the room, swapped power cords, and the
HP was not plugged into the same outlet as my
regular comp. Does this sound like bad wiring?
We've had some monster thunderstorms and a recent
lightning hit nearby, but they came after my
first PSU went. Any help would be really
appreciated!
Click to expand...

If the computer is old enough, there were some
computers long ago, where the PSU fan has a cable
which runs outside of the power supply. The PSU
fan is actually powered by the computer motherboard
fan header. That allows the motherboard to adjust the
fan speed. If the cable happens to be disconnected,
then you see what looks like a PSU fan failure.

It's also possible for a fan to stop turning. Inspect
the fan, to see if the bearing is friction free. With
power off, use a pencil tip, to see whether you can
easily turn the fan or not.

While you're inside the computer, see if you can locate
a two or three wire fan cable, that leads inside the PSU.
That could be the cable that needs to be plugged into the
motherboard.

If the fan is not turning, the power supply will likely
switch off on overheat, after enough time passes. A good
design, has a thermistor on one of the heatsinks, to detect
a lack of cooling, or an overload situation.

It's usually pretty easy to get a PSU casing open and
look inside. Just remember that there are a couple
big caps in there, that can be charged to 300 VDC.
Normally, the caps have a bleeder resistor across them.
A safety conscious tech, never assumes the bleeders work,
and that the caps continue to be dangerous.

(In this diagram, the bleeder resistors are R2 and R3, near the
top center of the diagram. C5 and C6 are dangerous.)

http://www.pavouk.org/hw/en_atxps.html

On some fans, the cabling is modular, and the fan can
be unplugged without touching other stuff. I've replaced
one fan on a PSU. It required removing the screws that hold
the fan in place, unplugging the cable, and installing a new
one. I had to remove one transparent piece of plastic, to complete
the repair, but otherwise, didn't even get close to the big
caps. You must be careful to put any insulation back in place,
the way you found it. Plastic is used to prevent the
component leads, from touching the chassis metal.

(The big caps inside the PSU are not candidates for the
"screwdriver technique". Maybe someone suggested in the past,
to stick a screwdriver tip across the two leads on a big cap like that.
If a cap is big enough, *don't do that*. The noise can be so loud,
you'll be deaf for ten minutes. Any time you work with big caps,
work out 1/2*C*V**2 and the number of joules involved. There is
a lot of energy stored in those caps. They're not to be trifled
with. The same kind of danger awaits you inside a microwave oven.
Nasty nasty cap.)

Paul
 
...comp is in the den, had one here for 8+ years. I blew out a fairly new
PSU 2
months ago. Replaced it, and today the comp died again. I set up an old
HP to
use, and now it's not booting. Fans turn but not on the PSU. . . .Does
this sound
like bad wiring?
Click to expand...

Sounds like a bad PSU. I had PSUs die four times in
28 years of home computing. One occasion was within
a month of installing a new PSU (replaced free by the
vendor.)
 
Don said:
Sounds like a bad PSU. I had PSUs die four times in
28 years of home computing. One occasion was within
a month of installing a new PSU (replaced free by the
vendor.)
Click to expand...

Probably all that year-round ice plays a role there. ;-)
 
Don Phillipson said:
Sounds like a bad PSU. I had PSUs die four times in
28 years of home computing.
Click to expand...

I have had better luck than that, using quality name brand power
supplies. I used one Antec for ages, through several upgrades.
--
 
Yes an outlet may "work" even when it is wired incorrectly or is now
faulty in one way or another.

In the USA the easiest way for someone to do a quick test on the 3-prong
wall outlets is to use one of these little testers. Many companies make
them but I usually find one at large home centers like Lowe's or Home
Depot when I need a replacement.

http://www.lowes.com/pd_292767-1270...=1&currentURL=/pl__0__s?Ntt=tetser&facetInfo=

or

http://www.lowes.com/pd_292761-1270...=1&currentURL=/pl__0__s?Ntt=tetser&facetInfo=

Both of them can do a basic test of a 3-prong outlet parts but if it was
me I'd buy the second unit or one like it. The kind with the little
button on it will also test the GFCI outlets/breakers used for possible
wet locations.

For what it's worth I've seen a local building inspector walking around
with one checking the outlets at new or remodel jobs from time to time.

I have found outlet strips, surge protectors, extension cords, and many
outlets wired incorrectly with mine.
 
You should buy a UPS. It is better to have one and not need it than
to need one and not have it. A good UPS will tell you if you have bad
power.

The power went out over here a week ago and I was web surfing in the
dark for about 30 min on my laptop.
Click to expand...

Yeah. It's amazing how often mine cuts in for a moment. Most of the
time it's so short the power supply capacitors would hold it but at
least once a month in the summer it's long enough to blink the lights
and reboot an unprotected PC.
 
Yeah. It's amazing how often mine cuts in for a moment. Most of the
time it's so short the power supply capacitors would hold it but at
least once a month in the summer it's long enough to blink the lights
and reboot an unprotected PC.
Click to expand...

Mine cut in not ten minutes ago. I didn't see the lights flicker but
something upset my UPS. I have my computer, monitor and 3 NAS devices on
it. This particular computer was prone to crashing, with or without
lights flickering. Since I acquired the UPS, no more crashing.
Definitely good value.

Krypsis
 
Mine comes on at all times during the day for a brief second maybe
twice a day. I haven't bothered to verify it, but I think it is
because I have an CFL in the desk lamp.
Click to expand...

Decent UPS-es often kick in far before the connected stuff would see a
problem with the inflow AC. It may be somewhat "crying wolf", but I'd
rather see/hear a few unexpected UPS flashes/beeps/screen notifications
(if connected to the target pc via a data cable) than the alternative.

It's just something you learn to live with.

This is just SWAG "Scientific Wild-Assed Guess", but the CFL could
easily be the cause. Try swapping in a plain bulb for a week or so.

I know the need for CFLs, but there's no money in the sales model to
account for crappy ones. I've had so many problems electrical and
interference problems with *all* brands of CFLs that I still keep a
supply of plain old "hot wire" bulbs on hand for those times when the
WiFi dies, the AM radios in the house are buzzed out, or I get "funky
breaker trips". I've had all these and more.

Right now, I've got at least 6 'open tickets' with CFL vendors over
defective bulbs. It's a waste of time, but at least it gets someone's
attention. A couple of years ago, I started an "email bitch" that
resulted in me getting a case of 24 75W equivalent CFLs without
notice... so bitching does work!


--
"Shit this is it, all the pieces do fit.
We're like that crazy old man jumping
out of the alleyway with a baseball bat,
saying, "Remember me motherfucker?"
Jim “Dandy” Mangrum
 
Decent UPS-es often kick in far before the connected stuff would see a
problem with the inflow AC. It may be somewhat "crying wolf", but I'd
rather see/hear a few unexpected UPS flashes/beeps/screen notifications
(if connected to the target pc via a data cable) than the alternative.
Click to expand...

Exactly. Most of the times the UPS kicks in it's crying wolf. It's
no big deal. One beep, a notice pops up and that's that. So what?
 
Exactly. Most of the times the UPS kicks in it's crying wolf. It's
no big deal. One beep, a notice pops up and that's that. So what?
Click to expand...


Eggzactly.... it's just knowing what to expect. Far too many n00bs will
literally "shit their pants" on that first beep.

I'm (unfortunately) the unpaid "IT Guy" for "friends and family".

You can guess the rest, but you didn't have to deal with the lathered-up
phone calls at "o-dark-thirty" over crap like this....

--
"Shit this is it, all the pieces do fit.
We're like that crazy old man jumping
out of the alleyway with a baseball bat,
saying, "Remember me motherfucker?"
Jim “Dandy” Mangrum
 
Eggzactly.... it's just knowing what to expect. Far too many n00bs will
literally "shit their pants" on that first beep.

I'm (unfortunately) the unpaid "IT Guy" for "friends and family".

You can guess the rest, but you didn't have to deal with the lathered-up
phone calls at "o-dark-thirty" over crap like this....
Click to expand...

If you know how to deal with these beasts you get the calls. At least
nobody except the office is going to call at o-dark-thirty.
 
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