On 5/1/2011 4:41 PM, Higgs Boson wrote:
On Apr 30, 3:49 pm, "larry moe 'n
wrote:
Higgs Boson wrote:

My computer (PC, 5+ years old; well-behaved), has started SCREAMING every few minutes.
It wants something, or is warning me of something.

I just paid a consultant pretty fair bux about two months ago to
upgrade, so I'm tapped out, computer-wise, but
scared to death I might be hearing a death rattle.

Any honest consultant who upgraded your computer just two months ago
will check your computer for free and charge you nothing for minor
repairs.

Hmm...never occurred to me. I'll call him& see how he reacts.

Stuff that can screech in a computer:

1. Fans -- in the power supply, on the CPU and maybe the graphics
card, in the case. Try stopping each fan momentarily and listen for
changes. Do NOT try to stop the power supply fan by sticking a
screwdriver into it because there's exposed high voltage all over the
interior of the power supply. Instead use a disposable plastic straw
because plastic doesn't conduct electricity, and disposable straws are
flexible and won't break off or break fan blades. Stick the straw(s)
in before turning on the PSU. Replace or relube noisy fans. Relubing
ball bearings usually doesn't help, but a drop of light machine oil
(5-10 weight) can silence sleeve bearings. Sometimes it's not the
bearings but a thrust washer that's screaming because of scoring or
distortion. Real hardware stores sell replacement washers, both metal
and plastic (nylon or delrin).

My knowledgeable neighbor came over& showed me how to take off the
cover -- piece of cake; I feel like a jerk for not noticing!
He checked the fan. Spins freely. WAS cleaned and dusted by
consulted, so that's not the prob.

NOTE: This computer has only ONE fan; doesn't have a separate one
for the processor or graphics card.. Is that a function of old
model? It's a Dell Dimension, only about 5-6 years old.

Fan cover fits well; no dust inside. Neighbor spun the fan; didn't
hang up or stick; not noisy. I'll do the test you suggested, but
don't know what "changes" to listen/watch for. COULD YOU ELUCIDATE.


2. Disk drives -- rarely. If the drive is identified on the BIOS boot-
up screen, it's highly unlikely the drive is screaming.

3. Speakers -- the audio circuitry may pick up noise because of buggy
software or because a filter capacitor is really bad and causing AC to
get into the circuitry's power.


Screaming heard even when outside speakers are not on. There is also
a tiny speaker inside, as some have pointed out. I'm not techie
enough to check on FILTER CAPACITORS but will ask my neighbor if that
rings a bell.


4. Inductors -- coils and transformers in the power supply, on the
mother board, and on most graphics cards. Sometimes their windings
are simply loose, but screaming that suddenly appears often indicates
bad capacitors, which can make transistors (MOSFETs) turn on and off
more gradually or make the output voltage low and cause a voltage
regulator to try too hard to compensate. Bad capacitors aren't
unusual in 5-year-old computers, and in the case of power-hungry
Pentium 4s, even quality brand capacitors. Also one of those quality
brands, Nichicon, had a bad run of HM and HN models from about
2001-2004. Seewww.BadCaps.netfor lots of information about such
problems. Bad caps can eventually make MOSFETs burn out.

Thank you for that precious (but over my headg) analysis. I'm
grateful for the heads-up about potential reasons for screaming, and
will bounce them off neighbor.
As well as calling consultant.

One thing neighbor did suggest: Put in a new mother board. But would
that address the SCREAMING problem?

TX

HB



Before you spend money on a new motherboard, be advised that many Dells
of your vintage used non-standard pinouts for the PS connection. Don't
recall offhand if the Dimension was one of them. Not a slam on you, but
given your lack of experience with computer innards, a motherboard swap
is likely to be a long, expensive, and frustrating experience. Since we
don't know where the screaming is coming from, it may or may not fix
problem. I'd try unplugging the internal speaker (if it isn't
hard-mounted to motherboard), and see if it makes a difference. But a
screaming sound is usually made by a moving part, and your computer
doesn't have many of those- drives and power supply fan.

My low-buck recommendation, based on my day job doing computer support,
and my former side gig of rebuilding/reselling computers (before cheap
new ones killed the market), is to look on CraigsList for a computer of
similar brand and vintage. Don't pay over 100 bucks for it. You can move
your hard drive over, as well as any components that are better than
what new machine has (like video and memory, if the sockets match.)

For just a little more $, you can get a new Dell entry-level system
online or from SamsClub or similar. I'm a cheap SOB, so I have never
purchased a new computer, but I have assisted others, and they were all
pleased with the performance of even entry-level new machines.

--
aem sends...