This is actually something I got to see firsthand after an old computer I had did an auto-shutdown due to an overheated CPU. I thought it was the fan at first, but the fan still works so my next guess was dust causing hot spots in the heat sink. I then noticed some capacitors on the motherboard were bulging, the way I understand it is that a budging capacitor can mean the component is close to failure.

What causes this to occur? Is it just normal wear or does it has to with abnormal voltages?

Strange, the motherboard to my old windows 98 has now outlasted the motherboard for a windows Xp.

I replace lots of bad caps on motherboards. Most will split and leak out the top. I work on security DVRs. They use a standard motherboard, different brands, all have shown failure in the electrolytic caps. Different problems will develop, depending on what failed. Take a good soldering iron and great care but they can be replaced. Most are 6.5v 1000, 1500 or 2200uf. If your computer is running slow or has booting problems, check the caps. I have replaced 50 or more last year. Most of these machines run 24-7, which may be why I see so much failure. They also fail on video cards. Sometimes its cheaper to buy a new card than replace the caps. Robert

Thanks WESTUPLACE, but unfortunately when I tried to pull the fan off to check the heat sink I didn't release the lock-tabs and it took the heat sink and the CPU with it. One of the pins on the CPU got bent when I tried to put the CPU and heat sink back in.

I'm thinking that the oveheating of the CPU may somehow be connected to the capacitors bulging.

Electrolytic capacitors are a failure item, they simply have a finite life span and eventually fail. Failures typically start to occur at around 5 years, but it depends on a lot of things- ambient conditions, power quality, etc.

Bigger capacitors can also fail in this way. Here's a 60uf from one of a pair of 3 hp single-phase motors running a 440v 3-phase generator. It had been getting a hammering when I let a couple of bozos loose on a big planer as a favor. They kept stalling and restarting it, too stupid to grasp the concept of a mechanical starting clutch. This was the result, [2007 pic]:



I fitted a new cap, no visible smoke let out! The other motor was apparently undamaged by the incident. Both have continued to run OK for the last couple of years .

Here's my set up, duplex 230v 3 hp motors running a 440v 3 phase generator with 1:1 vee-belt drive.



[The planer will not start, even with star delta, on 6hp gross output - it's a 20" beast with a 70 lb cutter block running @ 4500 rpm. I fitted a foot operated-clutch to ease her up to speed. The motor is 7.5hp, but I restrict the power by taking lighter cuts.]

The way you describe the planer that is pretty good size unit I have a 16 inch unit but unforetally it is not a electrique unit it is diesel driven but I put in a shear bolts in case someone jammed with hardwood and stall it.

{ it did happend couple time allready }

I know how long it take to get up to the running speed and I have one of my customer he have very serious sized planer IIRC it will take up to 48 inches that one have 2 motors in there one for planer head the second motor for feed drive { that one is a DC motor } the planer motor itself is 30HP that thing really screams once it get up running speed.

Merci,Marc

Gee Alan, that was a motor starting capacitor? I didn't know it could happen in commercial capacitors.

Here's my post from April 2005 describing some of my machines, which are almost all renovation projects.

My memory is not what it was, and I got some of the details wrong, it's a 6kw alternator.

The Robinson planer was bought to France in about 1992 after our work's carpentry shop closed down in the recession at that time. Funnily enough, I also originally ran it with a small diesel engine till I made an electrical conversion in 2004/5. The main problem was smoke from the stub exhaust and the noise - it was a hand cranked single cylinder job out of a Chinese tractor! Still got it [somewhere].

https://www.electrical-contractor.n...e_built_alternator_Some_.html#Post120645

If any of you work with UPS systems, the big DC and AC filter caps generally need replaced every 5 years as PM. If you dontt replace them pre-emptively, you may end up replacing far more expensive components, too.

Alan.,

Merci de la liaison de votre magasin de boiserie.

Thanks for the link about your woodwork shop.

The diesel engine I used it was Hatz that thing is loud all by it means but I have to make a overdrive belt set up to match up what the electrique motor speed required { it was set up for 3,000T/min }

Merci,Marc

Not just woodwork Marc, I'll tackle anything!

Here's my old Patrick lathe being used to regrind the kingpins off my '56 Renault tractor. The head and tail-stocks are jacked up on dummy oak blocks to get the necessary throw, then a small 230v tool-grinder motor is clamped to the toolpost. This was a bit scary as it created a one-bladed steel propeller - running on the lowest lathe speed of 450rpm it was nigh-on invisible! Between-centres mounted kingpin is balanced by a steel block on the faceplate and ran surprisingly vibration-free. Luckily the Patrick's wheels are on the back of the bed thus enabling this intrepid coward to keep well out of the way. My biggest problem was my wife discovering my best leather pants belt being cut up and used as a drive-belt on the lathe pulleys. It's a man thing!

All this on less than 400 watts and there are no capacitors on either motor.

Back to the original topic, there has been an epidemic of electrolytic capacitor failure in recent years, primarily due to cheaply manufactured caps, that were made using a stolen formula that omitted a key ingredient in the electrolyte.

http://en.wikipedia.org/wiki/Capacitor_plague
http://www.badcaps.net/pages.php?vid=4

I spent a few days recently repairing dozens of Samsung LCD monitors from our lab that all failed in the same way shortly after the warranty expired. Every one of them was a victim of the bulging capacitors in the power supply.

Thanks NJwirenut that information was helpful, especially the internet links.