OT - hardware - info sought about killing a PC (SOLVED)

[cobaka]

Hello All:

Dragged a desk-top out of solitary confinement. Connected kbd/monitor (etc) and booted.
Puppy ran for several days. (Power remained on). (Great, mate!)
Acer 661GX-M7 motherboard. Older system (came with only 512MiB RAM).

Opened case - saw dust bunnies - including in fan and around CPU heatsink. Lots of dust.
Here is my point of concern. Used a vacuum cleaner to clean the CPU fan. Foolish!
The fan spun up to (I would think) higher speed than normal running speed.
After some time I came understand the fan acted as a generator.
*Thinks* I might feed enough voltage into this little sucker to kill it! Stopped vacuuming.
From here on the detail is uncertain but now the system does not boot. (but see below).
When the power is turned on the fan runs momentarily, then stops.
Replaced CMOS battery - voltage measured at 0.9V. After that the system ran long enought to see a little of the BIOS settings - but while reading/checking the PC stopped and returned to the prev. state. That is - turn the power on - see the fan run momentarily. Nothing appears on the screen. Hear no post 'beeps'.

Other info
(1) PSU voltages appear within expected 5% of spec - but am waiting for a test unit that will test the PSU under load.
(2) Memory has not been replaced. (Ordered - not arrived.)
(3) Single memory stick moved between sockets. (Nothing changed).
(4) Removed memory - turned pwr on -> long constant beep.
(5) Have not examined the state of the 'run PSU' signal yet.
(6) Have not changed the PSU.

Question: Anyone here killed a fan (or more) by running the fan-speed up with a vacuum cleaner?

cobaka

[rockedge]

Did you disconnect the fan and try power on?

[Eastler_Dart]

hm, if I'm right in my older times working with Bios,
than its normal, that switch on, fan begins to run,
and after a short time it stops.
You switch on, for security fan gets started,
the bios loads complete, gets Info about the
temperature of the cpu -oh its cold- no fan needed
at the moment -> it stops the fan.
(Asume, your Board has a Cpu-temperature-sensor)

Is it possible, that your Fan is ok, but the connections
to VGA -> Monitor are broken? Check that cables

I have only to do with 2 Fans, goin in nirvana,
both had made loud noises while flying in the sky

Hope it helps - Eastler

[rockedge]

I have experienced the same after a vacuum and resetting the connectors from the power supply, re-seating the RAM modules fixed it for me.

is there a test button (very small) on the power supply?

What are the error lights showing?

[Fossil]

Check to see if a motherboard jumper - a small about 4x5x2 mm, usually black, plastic - circuit maker/breaker hasn't been dislodged or sucked up into the vacuum.

[Jasper]

..............might be worth re-applying some new thermal paste between the cpu and fan especially as it is an older build

[bigpup]

Check all the connection points on the motherboard.

Could have made one loose.

I would unplug and re-plug all connections.
Checking them for corrosion and making sure they plug back in completely.

If the fan is connected to the motherboard.
It is controlled by the detected temp of the CPU temp sensors.

If fan is connected to a power supply output cable.
It should run all the time power is on.

Well, you could have just broken the fan.

Be careful moving memory sticks around.

If you have any open memory slots not being used.

The motherboard usually has a specific location the memory sticks have to be placed in the memory slots.
Which slot has to be used based on number of sticks.

[cobaka]

Hello all! Thanks for your observations!

Below, on-going observations show the fault is not consistent. It will be difficult to find.
A second point: I got good suggestions about a probable cause. A thread on the forum should do two things. (1) answer the original point and (2) be useful at a later date. In other words, my replies should somehow impose some readability in the thread. (Or give some sort of a summary.)

Here is one example of a fault I dealt with some time in the past.
The ubiquitious @bigpup suggested re-seating connectors on the mother board. Vy good suggestion. How do I know that? Some years ago a fellows working for me designed a small uP system. Once booted it ran reliably for days, weeks, months. But it would fail to boot about one in 25 times. Toggle the reset line - bingo! Off it would go. I got "mad" with this fault. 4 hours later I found the problem: a race condition in the power-on jump logic. I added a small RC delay (100 ohm/22pF to the circuit. Solved. So Big-pup's observation <reseat the connectors> is good advice. A few tens of ohms (and parisitic capacitance) can slew a signal on any buss line. Remember: these lines clock at GHz. Nano-seconds matter!

Returning to the original point: What to do? My answer: Follow each suggestion given on my work-bench, but write only a summary here. At the same time I'll try to keep the logic of the fault-finding visible. So .. did the fan ruin the mother-board by generating excess voltage? OR did my 'poking' dislodge cables (etc) in some way that "nobbled"* it? Or am I the victim of a naughty PSU glitch?

*nobble: definition - disable a horse by drugging.

A recent observation. In short, the system is not consistently/completely dead. I replaced the CMOS battery. Before that I saw the main power (240V/on the wall) was off (had been off for some time. This may be an important observation. (The PC PSU has no on/off switch).
So: new battery, power on, fan ran, hit <del>, saw BIOS setting screen. 'Walked around' the bios settings for a minute or so - then .. fan stopped & PC died. Back to first observation.
Can turn power off ... wait ... power on ... fan runs/stops after < 1/2 sec. AND 3 kbd LEDs flash.

Three main possibilities:
Hypothesis (A). Fan as a generator nobbled the mother-board. (FGH)
Hypothesis (B) cables not connecting completely: (the big-pup hypothesis). Also known as 'the signal skewing hypo' (SKH).
PSU is suspect: i.e. it fails to start correctly of the main caps 'aren't' and the supply voltage is 'dipping' in sympathy with the mains frequency. (PSU.H)
Another possibility to explore: CMOS battery voltage when removed: 0.9 Volts. It's possible I need to reset the CMOS memory. There is a jumper

ALSO: Ordered x2 RAM sticks and PSU test unit. In transit as I write.
Now to answer specific points.
@rockedge fan disconnected. No change observed. Ran when re-connected. (but wait! There's more. With the connector to the fan 'out' it did not run. Reconnected: Runs momentarily. (*thinks* Fan connector must be faulty!! Test: disconnect. Fan motionless. Re-connect. Fan turns momentarily. Conclude: Fan connector is faulty. Ha!
Yes! I learned the truth from Lenny Bruce/ That all my wealth won't give me health/ And so I smoke a pint of tea a day.) OK. No more nonsense.

@Eastler_Dart (see above). Video cable well connected. Thanks.
@Jasper Thanks. Follow your point, but think I should unseat/reseat the CPU. Doubt the problem is heat-related. The fan only spins for 500mS - just a kick. Thought about reseating the CPU after reading note by bigpup.
@Fossil Will check for missing jumper - but generally I dislodge dust with small paint-brush (very gentle) and keep the vacuum nozzel well away from components. Big-pup says: re-seat all cables so I'll check jumpers when I do that. Am considering resetting bios. I think there is a jumper to do that.
@bigpup Re-seat all connectors? Great idea, but will wait until PSU test unit and fresh memory sticks arrive. (Also I did reseat memory and drive connectors.) Fan is def. OK, but my argument is with the whole PC. It won't boot, and a dead fan wouldn't (shouldn't) stop the system. Not until CPU temperature gets in Death Valley.

In general: This box is old and was good. I'm going to make a serious attempt to keep it running.

@rockedge I want to discuss this:

What are the error lights showing?

I'm quite unfamiliar with error lights. Looking at the manual, I don't see 'lights'. Do you mean a 'POST-test' card that plugs into a PCI slot?
About PSU test button. The pwr supply is basic. Can't see a small button (doesn't mean it's not there!) PSU doesn't have it's own on-off switch. This PC is about 15 y.o. so the PSU caps may be ageing.
Finally ... I mentioned the CMOS battery above. 0.9V when replaced. Possible I have 'weird settings' in there. Will explore this possiblity more.

As I wrote above: This PC is quite old, but I will revive it if possible.
To all. I appreciate your comments/observations.

Cobaka

[Marv]

What is the approximate year of manufacture of the system? I tried to look it up using the mobo number but had no success. It's been a looong time since I dealt with this, but from 1997 to 2005, there were a lot of bad electrolytic caps installed both in mobos and PSUs and I got pretty proficient at replacing them. Most of the failures occurred between 2002 and 2007 IIRC. If it is of that vintage, carefully inspect the main (largest) electrolytic capacitors on the mobo and in the PSU for any bulging on the top or leakage where they sit on the PC board. Anything made post 2005 should be OK in this respect.

Just a thought,

[Jasper]

@cobaka

I might be wrong but I do believe that if you look at your LED's on the external casing they will flash in a consistent pattern. Also, are you hearing a some beep sounds too?

That can be interpreted to diagnose the fault.

I think that is what @rockedge may be referring to.

As an example take a look here for a Dell troubleshooter (only as an explanation ... I know it's not your hardware setup!)

https://www.dell.com/support/kbdoc/en-u ... 10-systems

[rockedge]

I might be wrong but I do believe that if you look at your LED's on the external casing they will flash in a consistent pattern. Also, are you hearing a some beep sounds too?

That can be interpreted to diagnose the fault.

Yes! Exactly. Most machines have both methods or one or the other.

[bigpup]

What is the approximate year of manufacture of the system? I tried to look it up using the mobo number but had no success. It's been a looong time since I dealt with this, but from 1997 to 2005, there were a lot of bad electrolytic caps installed both in mobos and PSUs and I got pretty proficient at replacing them. Most of the failures occurred between 2002 and 2007 IIRC. If it is of that vintage, carefully inspect the main (largest) electrolytic capacitors on the mobo and in the PSU for any bulging on the top or leakage where they sit on the PC board. Anything made post 2005 should be OK in this respect.

This is a very good idea to check them, even if this computer is not in this age group.

[cobaka]

Hello All:

(1) Here I answer questions from recent postings.
(2) I suspend repair on this PC until two testing units (PSU & POST) I ordered arrive. Then I'll revive the project. I've gone about as far as I can go at the moment.

@Marv This PC is a desk-top (tower) Acer Aspire SA-80. Release date: 2007-Jan.
@Jasper Front Panel LEDs: Operation isn't consistent. (1) When mains (wall) power is 'off' for an extended time these LEDs (there are two) are active for about 1 .. 2 seconds. I hear the HDD begin to spin up. I see the CPU cooling fan spin. When the two LEDs extinguish the HDD and fan 'die' also.
(2) However, if the power is cut (completely off) for only a shorter interval - say 5mins - the LEDs remain on for a shorter time. If the power is off for 60 seconds the LEDs do not light or light for a vy brief interval.

I hear no 'beeps'. Also @BigPup Checked the appearance of the electrolytics. I have a good example of the appearance of 'stuffed' electros: a Dell from 2005. I see obviously bulging electolytic caps on the mobo.

I set the 'reset BIOS parameter' jumper on the mobo. No change.

I want to repair this Celeron 2600. I read some reviews that reported this PC as 'undesireable'. At that stage they were 2 .. 3 years old (i.e. 2010 - 2011). That's running Windows, of course. I want to see how this little doggie will run with uPupBB. (My hunch: quite well. But seeing is believing.)

That's all for the moment guys!

Cobaka.

[bigpup]

Checked the appearance of the electrolytics. I have a good example of the appearance of 'stuffed' electros: a Dell from 2005. I see obviously bulging electolytic caps on the mobo.

I little confusing.

The computer has no electrolytic bulging or leaking caps or it does?

[cobaka]

Sorry @bigpup.
I was imprecise. The caps on the Acer SA-80 (the PC under repair) all appear "A-OK"
I also have a Dell that fails to boot. The caps on this motherboard bulge visibly.
In addition this Dell was manufactured in the interval when the caps gave trouble.
See Wikipedia:
https://en.wikipedia.org/wiki/Dell
and

" ... Dell used faulty components for its PCs, particularly the 11.8 million OptiPlex desktop computers sold to businesses and governments from May 2003 to July 2005, that suffered from faulty capacitors."

On the topic of my non-booting Acer SA-80: After tracking many pages of info (on the net) I have some additional info - but will save that for later.
Better to present a concise description of the symptoms of the fault and the repair than submit other Puppians to a tortuous account of how I got there.

собака

[cobaka]

To: @bigpup, @Marv, @rockedge, @Eastler_Dart, @Fossil:

Hello all. Thank you for offering suggestions about this problem.
Now the PC is booting/OK I can say something. "Over-speeding" the CPU cooling fan using the air-flow from a vacuum cleaner did not kill the CPU, memory or the fan speed regulation circuit.
My humble Celeron-based PC is now running. Just needs more RAM. (It's coming). 512 MiBytes really does stretch the friendship!

I discovered:
1. A flat CMOS battery can defeat the booting process and make a perfectly good PC appear like trash.
2. If the CMOS battery is replaced it is important to follow the correct 'reset CMOS' procedure.
3. In this case a PCI POST test card was quite useful. I got a clue about where/where not to look for the problem.
4. I saw weird intermittent symptoms until the CMOS parameters were correctly set. At times pressing front-panel "reset" did nothing.
. . at other times pressing "reset" resulted in a perpetual reset cycle. I observed the [signal] reset line (using the POST-test card) become active- then my PC re-booted.
(5) If the CMOS battery in you PC is more than 5 or 6 years old - replace it!

I now have a 2006 vintage PC for testing Puppies from older kennels.

Again, thanks

собака.