long term reliablity computer boards

Tim wrote:


Look up the specs on the electrolytics used on the boards. Most have a 2000 hour life rating at the specified temperature. After that, the ESR starts to rise, causing the boards to fail.
BTW, my background is in mission critical electronics.

Around machine tools?
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83 days?????????

Sure, why not?
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Tim wrote:

Study it, learn from it, or pay the consequences. Leaving some modern electronics on 24/7 destroys it in short order. Long gone are the tube days when you could put a couple fingers between components

Dream on. Better yet, rent a power analyzer and look at the AC line for a few weeks. You will never see a pure sine wave. Some days you'll barely recognize that it is supposed to be a sine wave.
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I've seen a BUNCH of file servers consistantly run 4 to 5 years without failure. The PC I'm on now has been on for some 3 year now, and another in the office more than 5. I also had my first Accurite II on a digital mill go better than 25 years.
I will grant you your expertise, but I can assure you, my actual experiences have shown quite different.

Everyone knows computers and electric motors are anything but partners on the shop grid. If you can about your computers, battery back up power supplies make good low cost filters. Not perfect, but many times better than nothing at all.
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Tim wrote:

I have had new computers die in less than a year, due to bad electrolytics. One started randomly rebooting, and the other refused to turn on. Not all systems are the same, used the same, or built with the same grade of parts. Look at the motherboard and power supply in one of those servers and compare it to a cheaper desktop computer. You'll find a better grade of capacitors, and more attention to air flow in the design. You're comparing apples to crab apples.
The original XT motherboards are damn near impossible to kill but there isn't much there to generate heat, either.

Good for you. Now try running those servers in a 120 degree room with no air circulating and see how long they last. Have you never heard of derating components to extend the operating life, or the term MTBF? There is a reason most server rooms are cold. A/C is a lot cheaper than new servers. The same goes for a radio or TV control room. They aren't 60 to 68 degrees to make the operator comfortable.

Try that near a large industrial park sometime, in a building with over 300 SMPS power pieces of equipment. The harmonics and noise on the neutral will cause it to overheat. Decades ago, it was common to use two gauges smaller for the neutral on three phase. When they started having electrical fires n office buildings, they discovered that the harmonics was the cause, and require new systems to have the neutral larger than the three phases.
The whole industrial park and a small subdivion was on the same small substation. The spikes and surges caused the hundreds of UPS to complain constantly.
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Yeah, I used to have the same problems when I was turning mine off and on daily.

Why, if you are not going to provide adaquate cooling, you deserve what ever you get.

You're not listening. Again, if you don't isolate the computers from the electric motors, you deserve what ever you get.
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Tim wrote:

I have only seen clone XT motherboards go bad, and I rebuild lots of old XTs when Ihad a used computer business. Even the IBM AT mother boards had a higer failure rate than the clone XT boards whe tey went to the first custom chips, to eliminate the 'glue logic'.

Yawn. Always have to play the dumbass, don't you?
They weren't air conditioned back in the vacuum tube days, but the equipment was designed to work in higher temperatures. It was no fun sitting in a control room with the transmitter a few feet from your side in a room that was well over 100 degrees. Some of them had no herat, either.
One military radio & TV station I worked at had a steam plant on the other end of the building, but all the station got was whatever heat was left in the return lines, and that went to the offices. Some days it was below zero, and you sat next to the transmitter whenever you could, becasue it was closer to 32 degrees.

You have no reading comprehension. "the hundreds of UPS" weren't there for people to trip over.
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You're the one with the comprehension problem. This branch of the thread was clearly about leaving computers on 24-7, as opposed to switching them off daily. Who cares if you didn't have UPSs 30 years ago, or didn't properly cool your computer equipment. Try to keep up or abstain from calling someone a dumb ass, while you drift from one topic to the next.
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wrote:

Not quite what the Nichicon spec sheet here says: http://products.nichicon.co.jp/en/pdf/XJA043/e-hm.pdf
After 2000 hours at the specified conditions, leakage and ripple are still under initial specs.
That said, the cheap electrolytics on consumer motherboards are what usually goes bad the quickest, given otherwise good power and environmental conditions. I just had to pull one and stick in a spare, it'd been in service pretty much continuously for 5-6 years. The big caps all had bulgy ends. I'll try reviving it with some new caps, they're cheap and it's a fairly quick fix, if it works.
So for the O.P., I'd figure on a max lifetime of NEW boards at about 5 years. Used ones are a crapshoot. You might improve things with better-quality caps, assuming you have the facilities and ability for changing same.
Stan
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snipped-for-privacy@prolynx.com wrote:

That is all that most are warranted for, and rarely ar the run at full temperature, so you extend the useful life. Motherboards use 105 C rated electrolytics, but the boards are never run at that temperature, the 85 degree rated electrolytics drop like flies.

Use a grounded vacuum desoldering iron to remove the bad caps, and make sure to clean off any electrolyte that leaked. Inspect the traces near the bad caps for erosion of the copper before soldering in the new caps.

If the motherboard was built with cheap electrolytics, you may not get a year out of it. A lot of Chinese capacitors were made with a low grade electrolyte that causes the foil to be destroyed. It wasn't much better than the salt water used in early homemade electrolytic caps in the early days of radio. There were dire warnings not to use any electrolytics back then, because they would develop high leakage currents and burn up the power transformer.
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Karl Townsend wrote:

Have you checked out the industrial computer suppliers? There's a lot of folks in your shoes; I would expect that someone at least makes a PC-104 carrier with a regular ISA slot.
Search on "embedded PC" and "ISA", if you haven't already.
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On Wed, 29 Apr 2009 06:13:48 -0500, "Karl Townsend"

AMI made almost bulletproof boards way back. Whatever you get you will want to replace the Low ESR filter caps on the boards.(Generally a set of 8)
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Depends... I had some old XTs that just would not die. I still have drives out of some of them as working spares, and I have one "all media" computer that has some of those original XT floppy drives running today.
The real success story though is a 486 DX 80 that I bought 1st gen and threw in an old 386 cabinet. I ran that machine 24/7 more than a decade with no failures of anything. Drives, memory, processors, etc. In fact I think one of the floppy drives in it is from one of my 386 machines. The last 3 years I only power it up when I need it a couple times a week, but it still boots right up and runs like a champ. Only reason I shut it down now is that it has a nsiy power supply fan that drives me crazy. Can't complain. That power supply came with the cabinet, and my wife had that computer before we met. It was totally state of the art back then. LOL.
I have not had that luck with any computer newer than that however. Boards fail, memory fails, processors get flaky, drives fail, etc etc... However, I have managed to keep a lot of them going in a pinch just by slowing them down. Its kind of a shame that its not that easy with a modern BIOS.

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The motherboard i use takes a WIDE range of P4 processors. Would it be wise to buy a few slower ones to swap in a failing unit?
Karl
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Karl,
UMMM look back 20 or 30 years, when was the last time you saw a 8080 CP/M computer....
I'd seriously think about this statment you made...

I haven't seen a *NEW* 3.5 floopy drive in several years though someone *might* make them
PATA hard disks (you know connected by the wide flat cable) are NO LONGER MANUFACTURED... It's all SATA now (that skinny red cable)
FYI just to blow your mind, in the SATA world it's getting tough (at the OEM manufacturing level) to buy a SATA drive SMALLER than 750GB and as of last week the quotes a customer of mine got had 1TB (yes that's TERABYTE) drives at a lower cost than 750GB...
Good luck pal...
--.- Dave

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Dave August wrote:

IDE HDD's are still readily available , checked Newegg recently ?
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Till all the old stock is gone..
Read my post again, NO LONGER MANUFACTURED...
Sure Newegg et-all will sell ya "new old stock" till it's depleted... but they ain't making em any more.. case closed...
Trust me "SeeCrate" and "EasternAnalog" closed the PATA lines a year ago...
--.- Dave

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Dave August wrote:

Solid state hard drive prices are dropping rapidly. They are plug in replacements for mechanical hard drives. Standard power connectors & EIDE cables.
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    Hmm ... *that* should have better reliability. Assuming that they don't have the problem that some CF (Compact Flash) cards have when used for computer boot drives instead of camera media. They have a limited number of write cycles, so if you are booting from them and running a lot of things which write all the time, you will eventually run out of write cycles and it will get to be unreliable. If the solid state drives have gotten around that, they sound great. What kind of speeds do they offer?
    Enjoy,         DoN.
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"DoN. Nichols" wrote:

http://www.crucial.com/pdf/productFlyer/ProductFlyer_ssd.pdf
32GB: up to 100MB/s (read) 60MB/s (write) 64GB: up to 100MB/s (read) 35MB/s (write)
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